The value of this variable is the version of Emacs being run. It is a
string such as @code{"20.3.1"}. The last number in this string is not
really part of the Emacs release version number; it is incremented each
-time you build Emacs in any given directory. A value with three numeric
+time you build Emacs in any given directory. A value with four numeric
components, such as @code{"20.3.9.1"}, indicates an unreleased test
version.
@end defvar