Right now there isn't any formal way to deprecate only some specific
elements of an enum. So this is just documented.

You can deprecate all the enum using ATK_DISABLE_DEPRECATED like in
other projects, but if you try to do the same for some specific
elements, you will find problems when you compile the glib-mkenum
generated enum types (unless you want to break the ABI).

https://bugzilla.gnome.org/show_bug.cgi?id=697968