Document 'url-user-agent'.

* lisp/url/url-http.el (url-user-agent): Move from here...
* lisp/url/url-vars.el (url-user-agent): ...to here.  This is to
keep all the URL defcustoms in one place, and also have it defined
whenever the URL library is loaded.

* doc/misc/url.texi (Customization): Document 'url-user-agent'.

doc/misc/url.texi

@@ -1330,6 +1330,14 @@ Connect directly.
 @end table
 @end defopt
 
+@defopt url-user-agent
+The User Agent string used for sending HTTP/HTTPS requests.  The value
+should be a string or a function of no arguments that returns a
+string.  The default value is @w{@samp{User-Agent: @var{package-name}
+URL/Emacs}}, where @var{package-name} is the value of
+@code{url-package-name} and its version, if they are non-@code{nil}.
+@end defopt
+
 @node GNU Free Documentation License
 @appendix GNU Free Documentation License
 @include doclicense.texi

etc/NEWS

@@ -763,6 +763,7 @@ See the doc string of `sh-indent-after-continuation' for details.
 When `url-handler-mode' is enabled, file operations for these
 protocols as well as for "telnet" and "ftp" are passed to Tramp.
 
++++
 *** The URL package allows customizing the `url-user-agent' string.
 The new `url-user-agent' variable can be customized to be a string or
 a function.

lisp/url/url-http.el

@@ -135,17 +135,6 @@ request.")
     (507 insufficient-storage            "Insufficient storage"))
   "The HTTP return codes and their text.")
 
-(defcustom url-user-agent (format "User-Agent: %sURL/%s\r\n"
-				  (if url-package-name
-				      (concat url-package-name "/"
-					      url-package-version " ")
-				    "") url-version)
-  "User Agent used by the URL package."
-  :type '(choice (string :tag "A static User-Agent string")
-                 (function :tag "Call a function to get the User-Agent string"))
-  :version "25.1"
-  :group 'url)
-
 ;(eval-when-compile
 ;; These are all macros so that they are hidden from external sight
 ;; when the file is byte-compiled.

lisp/url/url-vars.el

@@ -357,6 +357,18 @@ Currently supported methods:
 		(const :tag "Direct connection" :value native))
   :group 'url-hairy)
 
+(defcustom url-user-agent (format "User-Agent: %sURL/%s\r\n"
+				  (if url-package-name
+				      (concat url-package-name "/"
+					      url-package-version " ")
+				    "") url-version)
+  "User Agent used by the URL package for HTTP/HTTPS requests
+Should be a string or a function of no arguments returning a string."
+  :type '(choice (string :tag "A static User-Agent string")
+                 (function :tag "Call a function to get the User-Agent string"))
+  :version "25.1"
+  :group 'url)
+
 (defvar url-setup-done nil "Has setup configuration been done?")
 
 (defconst url-weekday-alist