Well my skin supports custom pages, but nowhere in my skin I see a statement to include about.htt, so it is added automatically.
You don't see it explicitly, but these web pages are included in AlbumObject API, but they're not part of the ja:iterator iterating
But I have no idea what the difference is between 'hidden'and éxcluded'.
Excluded = Don't include in album
Hidden = Include in album, but don't show link to it / thumbnail for it