Last modified: 2008-02-07 15:20:28 UTC
Add a new function to list=categorymembers that allows filtering on timestamp (like rvstart and rvend for revisions). There appears to be an index on that field, so it should not be a performance problem.
I'll implement this tomorrow afternoon.
I think the reason nobody implemented it has nothing to do with performance; the use case for this feature is pretty obscure, so I guess nobody was crazy enough to come up with this :P
Added in r30670