NEWS

GNU Emacs NEWS -- history of user-visible changes.

Copyright (C) 2017-2021 Free Software Foundation, Inc.
See the end of the file for license conditions.

Please send Emacs bug reports to 'bug-gnu-emacs@gnu.org'.
If possible, use 'M-x report-emacs-bug'.

This file is about changes in Emacs version 28.

See file HISTORY for a list of GNU Emacs versions and release dates.
See files NEWS.27, NEWS.26, ..., NEWS.18, and NEWS.1-17 for changes
in older Emacs versions.

You can narrow news to a specific version by calling 'view-emacs-news'
with a prefix argument or by typing 'C-u C-h C-n'.

Temporary note:
+++ indicates that all relevant manuals in doc/ have been updated.
--- means no change in the manuals is needed.
When you add a new item, use the appropriate mark if you are sure it
applies, and please also update docstrings as needed.


* Installation Changes in Emacs 28.1

** Emacs now optionally supports native compilation of Lisp files.
To enable this, configure Emacs with the '--with-native-compilation' option.
This requires the libgccjit library to be installed and functional,
and also requires GCC and Binutils to be available when Lisp code is
natively compiled.  See the Info node "(elisp) Native Compilation" for
more details.

---
** Support for building with Motif has been removed.

** The Cairo graphics library is now used by default if present.
'--with-cairo' is now the default, if the appropriate development files
are found by 'configure'.  Note that building with Cairo means using
Pango instead of libXFT for font support.  Since Pango 1.44 has
removed support for bitmapped fonts, this may require you to adjust
your font settings.

Note also that 'FontBackend' settings in ".Xdefaults" or
".Xresources", or 'font-backend' frame parameter settings in your init
files, may need to be adjusted, as 'xft' is no longer a valid backend
when using Cairo.  Use 'ftcrhb' if your Emacs was built with HarfBuzz
text shaping support, and 'ftcr' otherwise.  You can determine this by
checking 'system-configuration-features'.  The 'ftcr' backend will
still be available when HarfBuzz is supported, but will not be used by
default.  We strongly recommend building with HarBuzz support.  'x' is
still a valid backend.

---
** Building without double buffering support.
'configure --with-xdbe=no' can now be used to disable double buffering
at build time.

---
** 'configure' now warns about building with libXft support.
libXft is unmaintained, and causes a number of problems with modern
fonts including but not limited to crashes; support for it may be
removed in a future version of Emacs.  Please consider using
Cairo + HarfBuzz instead.

---
** 'configure' now warns about not using HarfBuzz if using Cairo.
We want to encourage people to use the most modern font features
available, and this is the Cairo graphics library + HarfBuzz for font
shaping, so 'configure' now recommends that combination.

---
** The ftx font backend driver has been removed.
It was declared obsolete in Emacs 27.1.

---
** The configure option '--without-makeinfo' has been removed.
This was only ever relevant when building from a repository checkout.
This now requires makeinfo, which is part of the texinfo package.

---
** Support for building with '-fcheck-pointer-bounds' has been removed.
GCC has withdrawn the '-fcheck-pointer-bounds' option and support for
its implementation has been removed from the Linux kernel.

---
** Emacs no longer supports old OpenBSD systems.
OpenBSD 5.3 and older releases are no longer supported, as they lack
proper pty support that Emacs needs.


* Startup Changes in Emacs 28.1

** Emacs can support 24-bit color TTY without terminfo database.
If your text-mode terminal supports 24-bit true color, but your system
lacks the terminfo database, you can instruct Emacs to support 24-bit
true color by setting 'COLORTERM=truecolor' in the environment.  This is
useful on systems such as FreeBSD which ships only with "etc/termcap".

** Emacs now supports loading a Secure Computing filter.
This is supported only on capable GNU/Linux systems.  To activate,
invoke Emacs with the '--seccomp=FILE' command-line option.  FILE must
name a binary file containing an array of 'struct sock_filter'
structures.  Emacs will then install that list of Secure Computing
filters into its own process early during the startup process.  You
can use this functionality to put an Emacs process in a sandbox to
avoid security issues when executing untrusted code.  See the manual
page for 'seccomp' system call, for details about Secure Computing
filters.


* Changes in Emacs 28.1

+++
** Etags now supports the Mercury programming language.
See https://mercurylang.org.

+++
** Etags command line option '--declarations' now has Mercury-specific behavior.
All Mercury declarations are tagged by default.  However, for
compatibility with 'etags' support for Prolog, predicates and
functions appearing first in clauses will also be tagged if 'etags' is
invoked with the '--declarations' command-line option.

+++
** New command 'font-lock-update', bound to 'C-x x f'.
This command updates the syntax highlighting in this buffer.

** The new NonGNU ELPA archive is enabled by default alongside GNU ELPA.

+++
** New command 'recenter-other-window', bound to 'S-M-C-l'.
Like 'recenter-top-bottom' acting in the other window.

** Minibuffer scrolling is now conservative by default.
This is controlled by the new variable 'scroll-minibuffer-conservatively'.

In addition, there is a new variable
'redisplay-adhoc-scroll-in-resize-mini-windows' to disable the
ad-hoc auto-scrolling when resizing minibuffer windows.  It has been
found that its heuristic can be counter productive in some corner
cases, tho the cure may be worse than the disease.  This said, the
effect should be negligible in the vast majority of cases anyway.

+++
** Improved handling of minibuffers on switching frames.
By default, when you switch to another frame, an active minibuffer now
moves to the newly selected frame.  Nevertheless, the effect of what
you type in the minibuffer happens in the frame where the minibuffer
was first activated.  An alternative behavior is available by
customizing 'minibuffer-follows-selected-frame' to nil.  Here, the
minibuffer stays in the frame where you first opened it, and you must
switch back to this frame to continue or abort its command.  The old
behavior, which mixed these two, can be approximated by customizing
'minibuffer-follows-selected-frame' to a value which is neither nil
nor t.

+++
** New system for displaying documentation for groups of functions.
This can either be used by saying 'M-x shortdoc-display-group' and
choosing a group, or clicking a button in the "*Help*" buffers when
looking at the doc string of a function that belongs to one of these
groups.

---
** Improved "find definition" feature of *Help* buffers.
Now clicking on the link to find the definition of functions generated
by 'cl-defstruct', or variables generated by 'define-derived-mode',
for example, will go to the exact place where they are defined.

** New variable 'redisplay-skip-initial-frame' to enable batch redisplay tests.
Setting it to nil forces the redisplay to do its job even in the
initial frame used in batch mode.

---
** Support for the 'strike-through' face attribute on TTY frames.
If your terminal's termcap or terminfo database entry has the 'smxx'
capability defined, Emacs will now emit the prescribed escape
sequences necessary to render faces with the 'strike-through'
attribute on TTY frames.

+++
** Emacs now defaults to UTF-8 instead of ISO-8859-1.
This is only for the default, where the user has set no 'LANG' (or
similar) variable or environment.  This change should lead to no
user-visible changes for normal usage.

+++
** New variables that hold default buffer names for shell output.
The new constants 'shell-command-buffer-name' and
'shell-command-buffer-name-async' store the default buffer names
for the output of, respectively, synchronous and async shell
commands.

** Support for '(box . SIZE)' 'cursor-type'.
By default, 'box' cursor always has a filled box shape.  But if you
specify 'cursor-type' to be '(box . SIZE)', the cursor becomes a hollow
box if the point is on an image larger than SIZE pixels in any
dimension.

+++
** New user option 'word-wrap-by-category'.
When word-wrap is enabled, and this option is non-nil, that allows
Emacs to break lines after more characters than just whitespace
characters.  In particular, this significantly improves word-wrapping
for CJK text mixed with Latin text.

---
** Rudimentary support for the 'st' terminal emulator.
Emacs now supports 256 color display on the 'st' terminal emulator.

---
** Mouse wheel scrolling now works on more parts of frame's display.
When using 'mwheel-mode', the mouse wheel will now scroll also when
the mouse cursor is on the scroll bars, fringes, margins, header line,
and mode line.  ('mwheel-mode' is enabled by default on most graphical
displays.)

---
** Mouse wheel scrolling now defaults to one line at a time.

+++
** Mouse wheel scrolling with Shift modifier now scrolls horizontally.
This works in text buffers and over images.  Typing a numeric prefix arg
(e.g. 'M-5') before starting horizontal scrolling changes its step value.
The value is saved in the user option 'mouse-wheel-scroll-amount-horizontal'.

---
** The default value of 'frame-title-format' and 'icon-title-format' has changed.
These variables are used to display the title bar of visible frames
and the title bar of an iconified frame.  They now show the name of
the current buffer and the text "GNU Emacs" instead of the value of
'invocation-name'.  To get the old behavior back, add the following to
your init file:

    (setq frame-title-format '(multiple-frames "%b"
                              ("" invocation-name "@" system-name)))

+++
** 'nobreak-char-display' now also affects all non-ASCII space characters.
Previously, this was limited only to NO-BREAK-SPACE and hyphen
characters.  Now it also covers the rest of the non-ASCII Unicode
space characters.

---
** Prefer "chat.freenode.net" to "irc.freenode.net".
"chat.freenode.net" has been the preferred address for connecting to the
freenode IRC network for years now.  Occurrences of "irc.freenode.net"
have been replaced with "chat.freenode.net" throughout Emacs.

+++
** New functions 'null-device' and 'path-separator'.
These functions return the connection local value of the respective
variables.  This can be used for remote hosts.

** Emacs now prints a backtrace when signaling an error in batch mode.
This makes debugging Emacs Lisp scripts run in batch mode easier.  To
get back the old behavior, set the new variable
'backtrace-on-error-noninteractive' to a nil value.

** 'redisplay-skip-fontification-on-input' helps Emacs keep up with fast input.
This is another attempt to solve the problem of handling high key repeat rate
and other "slow scrolling" situations.  It is hoped it behaves better
than 'fast-but-imprecise-scrolling' and 'jit-lock-defer-time'.
It is not enabled by default.

+++
** Modifiers now go outside angle brackets in pretty-printed key bindings.
For example, 'RET' with Control and Meta modifiers is now shown as
'C-M-<return>' instead of '<C-M-return>'.  Either variant can be used
as input; functions such as 'kbd' and 'read-kbd-macro' accept both
styles as equivalent (they have done so for a long time).

+++
** New user option 'lazy-highlight-no-delay-length'.
Lazy highlighting of matches in Isearch now starts immediately if the
search string is at least this long.  'lazy-highlight-initial-delay'
still applies for shorter search strings, which avoids flicker in the
search buffer due to too many matches being highlighted.

+++
** A new keymap for buffer actions has been added.
The 'C-x x' keymap now holds keystrokes for various buffer-oriented
commands.  The new keystrokes are 'C-x x g' ('revert-buffer'),
'C-x x r' ('rename-buffer'), 'C-x x u' ('rename-uniquely'), 'C-x x n'
('clone-buffer'), 'C-x x i' ('insert-buffer'), 'C-x x t'
('toggle-truncate-lines') and 'C-x x f' ('font-lock-update').

---
** Commands 'set-frame-width' and 'set-frame-height' can now get their
input using the minibuffer.

---
** New user option 'bookmark-menu-confirm-deletion'.
In Bookmark Menu mode, Emacs by default does not prompt for
confirmation when you type 'x' to execute the deletion of bookmarks
that have been marked for deletion.  However, if this new option is
non-nil then Emacs will require confirmation with 'yes-or-no-p' before
deleting.

---
** New help window when Emacs prompts before opening a large file.
Commands like 'find-file' or 'visit-tags-table' ask to visit a file
normally or literally when the file is larger than a certain size (by
default, 9.5 MiB).  Press '?' or 'C-h' in that prompt to read more
about the different options to visit a file, how you can disable the
prompt, and how you can tweak the file size threshold.

+++
** Improved support for terminal emulators that encode the Meta flag.
Some terminal emulators set the 8th bit of Meta characters, and then
encode the resulting character code as if it were non-ASCII character
above codepoint 127.  Previously, the only way of using these in Emacs
was to set up the terminal emulator to use the 'ESC' characters to send
Meta characters to Emacs, e.g., send "ESC x" when the user types
'M-x'.  You can now avoid the need for this setup of such terminal
emulators by using the new input-meta-mode with the special value
'encoded' with these terminal emulators.


* Editing Changes in Emacs 28.1

+++
** A prefix arg now causes 'delete-other-frames' to only iconify frames.

+++
** The "Edit => Clear" menu item now obeys a rectangular region.

+++
** New command 'execute-extended-command-for-buffer'.
This new command, bound to 'M-S-x', works like
'execute-extended-command', but limits the set of commands to the
commands that have been determined to be particularly useful with the
current mode.

+++
** New user option 'read-extended-command-predicate'.
This user option controls how 'M-x' performs completion of commands when
you type 'TAB'.  By default, any command that matches what you have
typed is considered a completion candidate, but you can customize this
option to exclude commands that are not applicable to the current
buffer's major and minor modes, and respect the command's completion
predicate (if any).

---
** 'eval-expression' now no longer signals an error on incomplete expressions.
Previously, typing 'M-: ( RET' would result in Emacs saying "End of
file during parsing" and dropping out of the minibuffer.  The user
would have to type 'M-: M-p' to edit and redo the expression.  Now
Emacs will echo the message and allow the user to continue editing.

+++
** 'eval-last-sexp' now handles 'defvar'/'defcustom'/'defface' specially.
This command would previously not redefine values defined by these
forms, but this command has now been changed to work more like
'eval-defun', and reset the values as specified.

+++
** Standalone 'M-y' allows interactive selection from previous kills.
'M-y' can now be typed after a command that is not a yank command.
When invoked like that, it prompts in the minibuffer for one of the
previous kills, offering completion and minibuffer-history navigation
through previous kills recorded in the kill ring.  A similar feature
in Isearch can be invoked if you bind 'C-s M-y' to the command
'isearch-yank-pop'.  When the user option 'yank-from-kill-ring-rotate'
is nil the kill ring is not rotated after 'yank-from-kill-ring'.

---
** New user options 'copy-region-blink-delay' and 'delete-pair-blink-delay'.
'copy-region-blink-delay' specifies a delay to indicate the region
copied by 'kill-ring-save'.  'delete-pair-blink-delay' specifies
a delay to show a paired character to delete.

+++
** New command 'undo-redo'.
It undoes previous undo commands, but doesn't record itself as an
undoable command.

+++
** 'read-number' now has its own history variable.
Additionally, the function now accepts a HIST argument which can be
used to specify a custom history variable.

+++
** Input history for 'goto-line' can now be made local to every buffer.
In any event, line numbers used with 'goto-line' are kept in their own
history list.  This should help make faster the process of finding
line numbers that were previously jumped to.  By default, all buffers
share a single history list.  To make every buffer have its own
history list, customize the user option 'goto-line-history-local'.

+++
** New command 'goto-line-relative' to use in a narrowed buffer.
It moves point to the line relative to the accessible portion of the
narrowed buffer.  'M-g M-g' in Info is rebound to this command.
When 'widen-automatically' is non-nil, 'goto-line' widens the narrowed
buffer to be able to move point to the inaccessible portion.
'goto-line-relative' is bound to 'C-x n g'.

+++
** When called interactively, 'goto-char' now offers the number at
point as default.

+++
** When 'suggest-key-bindings' is non-nil, the completion list of 'M-x'
shows equivalent key bindings for all commands that have them.

** Autosaving via 'auto-save-visited-mode' can now be inhibited by
setting the variable 'auto-save-visited-mode' buffer-locally to nil.

** New commands to describe buttons and widgets have been added.
'widget-describe' (on a widget) will pop up a help buffer and give a
description of the properties.  Likewise 'button-describe' does the
same for a button.

** Obsolete aliases are no longer hidden from command completion.
Completion of command names now considers obsolete aliases as
candidates, if they were marked obsolete in the current major version
of Emacs.  Invoking a command via an obsolete alias now mentions the
obsolescence fact and shows the new name of the command.

+++
** New command 'revert-buffer-with-fine-grain'.
Revert a buffer trying to be as non-destructive as possible,
preserving markers, properties and overlays.  The new variable
'revert-buffer-with-fine-grain-max-seconds' specifies the maximum
number of seconds that 'revert-buffer-with-fine-grain' should spend
trying to be non-destructive.

+++
** New command 'memory-report'.
This command opens a new buffer called "*Memory Report*" and gives a
summary of where Emacs is using memory currently.

+++
** New user option 'isearch-repeat-on-direction-change'.
When this option is set, direction changes in Isearch move to another
search match, if there is one, instead of moving point to the other
end of the current match.

** Outline

+++
*** New commands to cycle heading visibility.
Typing 'TAB' on a heading line cycles the current section between
"hide all", "subheadings", and "show all" states.  Typing 'S-TAB'
anywhere in the buffer cycles the whole buffer between "only top-level
headings", "all headings and subheadings", and "show all" states.

*** New user option 'outline-minor-mode-cycle'.
This user option customizes 'outline-minor-mode', with the difference
that 'TAB' and 'S-TAB' on heading lines cycle heading visibility.
Typing 'TAB' on a heading line cycles the current section between
"hide all", "subheadings", and "show all" states.  Typing 'S-TAB' on a
heading line cycles the whole buffer between "only top-level
headings", "all headings and subheadings", and "show all" states.

*** New user option 'outline-minor-mode-highlight'.
This user option customizes 'outline-minor-mode'.  It puts
highlighting on heading lines using standard outline faces.  This
works well only when there are no conflicts with faces used by the
major mode.


* Changes in Specialized Modes and Packages in Emacs 28.1

** Completion List Mode
New key bindings have been added: 'n' and 'p' to navigate completions,
and 'M-g M-c' to switch to the minibuffer, and you can also switch back
to the completion list buffer with 'M-g M-c'.

** Benchmark
*** New function 'benchmark-call' to measure the execution time of a function.
Additionally, the number of repetitions can be expressed as a minimal duration
in seconds.

** Macroexp
---
*** New function 'macroexp-file-name' to know the name of the current file.
---
*** New function 'macroexp-compiling-p' to know if we're compiling.
---
*** New function 'macroexp-warn-and-return' to help emit warnings.
This used to be named 'macroexp--warn-and-return' and has proved useful
and well-behaved enough to lose the "internal" marker.

** 'blink-cursor-mode' is now enabled by default regardless of the UI.
It used to be enabled when Emacs is started in GUI mode but not when started
in text mode.  The cursor still only actually blinks in GUI frames.

** Bindat

+++
*** New 'Bindat type expression' description language.
This new system is provided by the new macro 'bindat-type' and
obsoletes the old data layout specifications.  It supports
arbitrary-size integers, recursive types, and more.  See the Info node
"(elisp) Byte Packing" in the ELisp manual for more details.

** pcase

+++
*** The 'or' pattern now binds the union of the vars of its sub-patterns.
If a variable is not bound by the subpattern that matched, it gets bound
to nil.  This was already sometimes the case, but it is now guaranteed.

+++
*** The 'pred' pattern can now take the form '(pred (not FUN))'.
This is like '(pred (lambda (x) (not (FUN x))))' but results
in better code.

---
*** New function 'pcase-compile-patterns' to write other macros.

+++
** profiler.el
The results displayed by 'profiler-report' now have the usage figures
at the left hand side followed by the function name.  This is intended
to make better use of the horizontal space, in particular eliminating
the truncation of function names.  There is no way to get the former
layout back.

** Loading dunnet.el in batch mode doesn't start the game any more.
Instead you need to do "emacs -f dun-batch" to start the game in
batch mode.

** Emacs Server

+++
*** New user option 'server-client-instructions'.
When emacsclient connects, Emacs will (by default) output a message
about how to exit the client frame.  If 'server-client-instructions'
is set to nil, this message is inhibited.

+++
*** New command 'server-edit-abort'.
This command (not bound to any key by default) can be used to abort
an edit instead of marking it as "Done" (which the 'C-x #' command
does).  The 'emacsclient' program exits with an abnormal status as
result of this command.

** Perl mode

---
*** New face 'perl-non-scalar-variable'.
This is used to fontify non-scalar variables.

** Python mode

*** 'python-shell-interpreter' now defaults to python3 on systems with python3.

*** 'C-c C-r' can now be used on arbitrary regions.
The command previously extended the start of the region to the start
of the line, but will now actually send the marked region, as
documented.

** Ruby mode

*** 'ruby-use-smie' is declared obsolete.
SMIE is now always enabled and 'ruby-use-smie' only controls whether
indentation is done using SMIE or with the old ad-hoc code.

** Icomplete

+++
*** New minor mode 'icomplete-vertical-mode', alias 'fido-vertical-mode'.
This mode is intended to be used with Icomplete ('M-x icomplete-mode')
or Fido ('M-x fido-mode'), to display the list of completions
candidates vertically instead of horizontally.  When used with
Icomplete, completions are rotated and selection kept at the top.
When used with Fido, completions scroll like a typical dropdown
widget.

*** Default value of 'icomplete-compute-delay' has been changed to 0.15 s.

*** Default value of 'icomplete-max-delay-chars' has been changed to 2.

*** Reduced blinking while completing the next completions set.
Icomplete doesn't hide the hint with the previously computed
completions anymore when compute delay is in effect, or the previous
computation has been aborted by input.  Instead it shows the previous
completions until the new ones are ready.

---
** Specific warnings can now be disabled from the warning buffer.
When a warning is displayed to the user, the resulting buffer now has
buttons which allow making permanent changes to the treatment of that
warning.  Automatic showing of the warning can be disabled (although
it is still logged to the "*Messages*" buffer), or the warning can be
disabled entirely.

** mspool.el

---
*** Autoload the main entry point 'mspool-show'.

** Windmove

*** New user options to customize windmove keybindings.
These options include 'windmove-default-keybindings',
'windmove-display-default-keybindings',
'windmove-delete-default-keybindings',
'windmove-swap-states-default-keybindings'.

** Windows

+++
*** New option 'delete-window-choose-selected'.
This allows to choose a frame's selected window after deleting the
previously selected one.

+++
*** New argument NO-OTHER for some window functions.
'get-lru-window', ‘get-mru-window’ and 'get-largest-window' now accept a
new optional argument NO-OTHER which, if non-nil, avoids returning a
window whose 'no-other-window' parameter is non-nil.

+++
*** New 'display-buffer' function 'display-buffer-use-least-recent-window'.
This is like 'display-buffer-use-some-window', but won't reuse the
current window, and when called repeatedly will try not to reuse a
previously selected window.

*** New function 'window-bump-use-time'.
This updates the use time of a window.

*** The key prefix 'C-x 4 1' displays next command buffer in the same window.
It's bound to the command 'same-window-prefix' that requests the buffer
of the next command to be displayed in the same window.

*** The key prefix 'C-x 4 4' displays next command buffer in a new window.
It's bound to the command 'other-window-prefix' that requests the buffer
of the next command to be displayed in a new window.

** Frames

*** The key prefix 'C-x 5 5' displays next command buffer in a new frame.
It's bound to the command 'other-frame-prefix' that requests the buffer
of the next command to be displayed in a new frame.

** Tab Bars

*** The key prefix 'C-x t t' displays next command buffer in a new tab.
It's bound to the command 'other-tab-prefix' that requests the buffer
of the next command to be displayed in a new tab.

+++
*** New command 'C-x t C-r' to open file read-only in other tab.

---
*** The tab bar is frame-local when 'tab-bar-show' is a number.
Show/hide the tab bar independently for each frame, according to the
value of 'tab-bar-show'.

---
*** New command 'toggle-frame-tab-bar'.
It can be used to enable/disable the tab bar individually on each frame
independently from the value of 'tab-bar-mode' and 'tab-bar-show'.

---
*** New user option 'tab-bar-format' defines a list of tab bar items.
When it contains 'tab-bar-format-global' (possibly appended after
'tab-bar-format-align-right'), then after enabling 'display-time-mode'
(or any other mode that uses 'global-mode-string') it displays time
aligned to the right on the tab bar instead of the mode line.
When 'tab-bar-format-tabs' is replaced with 'tab-bar-format-tabs-groups',
then the tab bar displays tab groups.

---
*** 'Mod-9' bound to 'tab-last' now switches to the last tab.
It also supports a negative argument.

---
*** New command 'tab-duplicate' bound to 'C-x t n'.

---
*** 'C-x t N' creates a new tab at the specified absolute position.
It also supports a negative argument.

---
*** 'C-x t M' moves the current tab to the specified absolute position.
It also supports a negative argument.

---
*** 'C-x t G' assigns a group name to the tab.
'tab-close-group' can close all tabs that belong to the selected group.
The user option 'tab-bar-new-tab-group' defines the default group of a
new tab.  After customizing 'tab-bar-tab-post-change-group-functions'
to 'tab-bar-move-tab-to-group', changing the tab group will also move it
closer to other tabs in the same group.

---
*** New user option 'tab-bar-tab-name-format-function'.

---
*** New user option 'tab-line-tab-name-format-function'.

---
*** The tabs in the tab line can now be scrolled using horizontal scroll.
If your mouse or trackpad supports it, you can now scroll tabs when
the mouse pointer is in the tab line by scrolling left or right.

---
*** New tab-line faces and options.
The face 'tab-line-tab-special' is used for tabs whose buffers are
special, i.e. not file-backed.  The face
'tab-line-tab-inactive-alternate' is used to display inactive tabs
with an alternating background color, making them easier to
distinguish between, especially if the face 'tab-line-tab' is
configured to not display with a box; this alternate face is only
applied when the option 'tab-line-tab-face-functions' is
so-configured.  That option may also be used to customize tab-line
faces in other ways.

** Occur mode

*** New bindings in occur-mode, 'next-error-no-select' bound to 'n' and
'previous-error-no-select' bound to 'p'.

*** The new command 'recenter-current-error', bound to 'l' in Occur or
compilation buffers, recenters the current displayed occurrence/error.

** EIEIO

+++
*** The macro 'oref-default' can now be used with 'setf'.
It is now defined as a generalized variable that can be used with
'setf' to modify the value stored in a given class slot.

** New minor mode 'cl-font-lock-built-in-mode' for 'lisp-mode'.
The mode provides refined highlighting of built-in functions, types,
and variables.

** Archive mode

---
*** Archive Mode can now parse ".squashfs" files.

*** Can now modify members of 'ar' archives.

*** Display of summaries unified between backends.

*** New user option 'archive-hidden-columns' and command
'archive-hideshow-column'.  These let you control which columns are
displayed and which are kept hidden.

---
*** New command bound to 'C': 'archive-copy-file'.
This command extracts the file under point and writes the data to a
file.

** Emacs Lisp mode

*** The mode-line now indicates whether we're using lexical or dynamic scoping.

*** A space between an open paren and a symbol changes the indentation rule.
The presence of a space between an open paren and a symbol now is
taken as a statement by the programmer that this should be indented
as a data list rather than as a piece of code.

** Calendar

+++
*** New user option 'calendar-time-zone-style'.
If 'numeric', calendar functions (eg 'calendar-sunrise-sunset') that display
time zones will use a form like "+0100" instead of "CET".

** Dired

---
*** Behavior change on 'dired-clean-confirm-killing-deleted-buffers'.
Previously, if 'dired-clean-up-buffers-too' was non-nil, and
'dired-clean-confirm-killing-deleted-buffers' was nil, the buffers
wouldn't be killed.  This combination will now kill the buffers.

+++
*** New user option 'dired-switches-in-mode-line'.
This user option controls how 'ls' switches are displayed in the mode
line, and allows truncating them (to preserve space on the mode line)
or showing them literally, either instead of, or in addition to,
displaying "by name" or "by date" sort order.

+++
*** New user option 'dired-compress-directory-default-suffix'.
This user option controls default suffix for compressing a directory.
If it's nil, ".tar.gz" will be used.  Refer to
'dired-compress-files-alist' for a list of supported suffixes.

+++
*** New user option 'dired-compress-file-default-suffix'.
This user option controls the default suffix for compressing files.
If it's nil, ".gz" will be used.  Refer to 'dired-compress-file-alist'
for a list of supported suffixes.

---
*** Broken and circular links are shown with the 'dired-broken-symlink' face.

*** '=' ('dired-diff') will now put all backup files into the 'M-n' history.
When using '=' on a file with backup files, the default file to use
for diffing is the newest backup file.  You can now use 'M-n' to quickly
select a different backup file instead.

+++
*** New user option 'dired-maybe-use-globstar'.
If set, enables globstar (recursive globbing) in shells that support
this feature, but turn it off by default.  This allows producing
directory listings with files matching a wildcard in all the
subdirectories of a given directory.  The new variable
'dired-enable-globstar-in-shell' lists which shells can have globstar
enabled, and how to enable it.

+++
*** New user option 'dired-copy-dereference'.
If set to non-nil, Dired will dereference symbolic links when copying.
This can be switched off on a per-usage basis by providing
'dired-do-copy' with a 'C-u' prefix.

*** New user option 'dired-do-revert-buffer'.
Non-nil reverts the destination Dired buffer after performing one
of these operations: 'dired-do-copy', 'dired-do-rename',
'dired-do-symlink', 'dired-do-hardlink'.

*** New user option 'dired-mark-region' affects all Dired commands
that mark files.  When non-nil and the region is active in Transient
Mark mode, then Dired commands operate only on files in the active
region.  The values 'file' and 'line' of this user option define the
details of marking the file at the end of the region.

*** State changing VC operations are supported in Dired on files and
directories with the help of new command 'dired-vc-next-action'.

+++
*** 'dired-jump' and 'dired-jump-other-window' moved from 'dired-x' to 'dired'.
The 'dired-jump' and 'dired-jump-other-window' commands have been
moved from the 'dired-x' package to 'dired'.  The user option
'dired-bind-jump' no longer has any effect and is now obsolete.
The commands are now bound to 'C-x C-j' and 'C-x 4 C-j' by default.

To get the old behavior of 'dired-bind-jump' back and unbind the above
keys, add the following to your init file:

(global-set-key "\C-x\C-j" nil)
(global-set-key "\C-x4\C-j" nil)

** Change Logs and VC

*** More VC commands can be used from non-file buffers.
The relevant commands are those that don't change the VC state.
The non-file buffers which can use VC commands are those that have
their 'default-directory' under VC.

*** New command 'vc-dir-root' uses the root directory without asking.

---
*** New face 'log-view-commit-body'.
This is used when expanding commit messages from 'vc-print-root-log'
and similar commands.

---
*** New faces for 'vc-dir' buffers.
Those are: 'vc-dir-header', 'vc-dir-header-value', 'vc-dir-directory',
'vc-dir-file', 'vc-dir-mark-indicator', 'vc-dir-status-warning',
'vc-dir-status-edited', 'vc-dir-status-up-to-date',
'vc-dir-status-ignored'.

---
*** The responsible VC backend is now the most specific one.
'vc-responsible-backend' loops over the backends in
'vc-handled-backends' to determine which backend is responsible for a
specific (unregistered) file.  Previously the first matching backend
was chosen, but now the one with the most specific path is chosen (in
case there's a directory handled by one backend inside another).

*** New commands 'vc-dir-mark-registered-files' (bound to '* r') and
'vc-dir-mark-unregistered-files'.

*** Support for bookmark.el.
Bookmark locations can refer to VC directory buffers.

---
*** New user option 'vc-hg-create-bookmark'.
It controls whether a bookmark or branch will be created when you
invoke 'C-u C-x v s' ('vc-create-tag').

---
*** 'vc-hg' now uses 'hg summary' to populate extra 'vc-dir' headers.

---
*** New user option 'vc-git-revision-complete-only-branches'.
If non-nil, only branches and remotes are considered when doing
completion over Git branch names.  The default is nil, which causes
tags to be considered as well.

---
*** New user option 'vc-git-log-switches'.
String or list of strings specifying switches for Git log under VC.

** Gnus

+++
*** The '#' command in the Group and Summary buffer now toggles,
instead of sets, the process mark.

+++
*** New user option 'gnus-process-mark-toggle'.
If non-nil (the default), the '#' command in the Group and Summary
buffers will toggle, instead of set, the process mark.


+++
*** New user option 'gnus-registry-register-all'.
If non-nil (the default), create registry entries for all messages.
If nil, don't automatically create entries, they must be created
manually.

+++
*** New user options to customise the summary line specs "%[" and "%]".
Four new options introduced in customisation group
'gnus-summary-format'.  These are 'gnus-sum-opening-bracket',
'gnus-sum-closing-bracket', 'gnus-sum-opening-bracket-adopted', and
'gnus-sum-closing-bracket-adopted'.  Their default values are "[", "]",
"<", ">" respectively.  These options control the appearance of "%["
and "%]" specs in the summary line format.  "%[" will normally display
the value of 'gnus-sum-opening-bracket', but can also be
'gnus-sum-opening-bracket-adopted' for the adopted articles.  "%]" will
normally display the value of 'gnus-sum-closing-bracket', but can also
be 'gnus-sum-closing-bracket-adopted' for the adopted articles.

+++
*** New user option 'gnus-paging-select-next'.
This controls what happens when using commands like 'SPC' and 'DEL' to
page the current article.  If non-nil (the default), go to the
next/prev article, but if nil, do nothing at the end/start of the article.

+++
*** New gnus-search library.
A new unified search syntax which can be used across multiple
supported search engines.  Set 'gnus-search-use-parsed-queries' to
non-nil to enable.

+++
*** New value for user option 'smiley-style'.
Smileys can now be rendered with emojis instead of small images when
using the new 'emoji' value in 'smiley-style'.

+++
*** New user option 'gnus-agent-eagerly-store-articles'.
If non-nil (which is the default), the Gnus Agent will store all read
articles in the Agent cache.

+++