VALUE should be a list with the form (PACKAGE . VERSION)
specifying that the variable was first introduced, or its
default value was changed, in PACKAGE version VERSION. This
- keyword takes priority over :version. The PACKAGE and VERSION
+ keyword takes priority over :version. For packages which
+ are bundled with Emacs releases, the PACKAGE and VERSION
must appear in the alist `customize-package-emacs-version-alist'.
Since PACKAGE must be unique and the user might see it in an
error message, a good choice is the official name of the