Thread:Talk:Extension default namespaces/Notes/reply

Negative numbers are reserved for special case pseudo-namespaces (special and media), DO NOT USE THEM UNDER ANY CIRCUMSTANCES for actual namespaces -- things will break.

All non-pseudo namespaces in the current system come in [subject, talk] pairs such that subject mod 2 = 0 and subject + 1 = talk. If you violate these constraints, things will break.

Namespace numbers between 0 and 99 are implicitly reserved for MediaWiki's internal use, and no custom or extension namespaces should be assigned there to avoid conflicting with future additions in MediaWiki.

Site-specific custom namespaces are generally assigned in the 100 to 199 range. I would recommend staying out of this range for anything to be defined by an extension.

The 200 to 299 range is probably a good place to register extension namespaces.

I would recommend against "absurdly large" numbers as those would be annoying. ;) However something more like, say 2000 might be just fine.