I'd like my extension's new special page to go under a new special page group in Special:SpecialPages, since it doesn't fit in any of the other categories, and it seems a bit silly to just stick it under "Other".
However, it looks like you can't just add a new message and expect Special:SpecialPages to pick it up. For example, if my new group were, just for example, "Pages which Manipulate the Space Time Continuum", I would have thought that doing this would be sufficient:
1. Add a new message to your extension's internationalization file:
$messages['en'] = array(
'myext' => 'My Bunch of Pages',
'specialpages-group-spacetime' => 'Pages which Manipulate the Space Time Continuum'
);
2. Categorize the special page (in this case, Special:TimeMachine:
$wgSpecialPageGroups['TimeMachine'] = 'spacetime';
So why doesn't this work? A quick perusal of the source code in SpecialPageFactory.php doesn't seem to turn up anything additional to do...
Thanks,
--Rob