The case I have right now is in manually changing the destination page of a stashed file that came from a .tar package, after I've removed the unpacked files that I don't want. It tries to look up the destination and display a warning if needed. The function that does that is looking to put the warning in an element found by name, using the name with numbers in it from before the row was renumbered.
I think this is a somewhat broader issue than just that warning - I need to be very careful about using those ID names with numbers in them, and wherever possible, I need to use jquery searches to find the elements by their class names instead.
Unfortunately, I'm trying to change the existing Special:Upload code as little as possible, and it uses names. (Though since the patch I submitted hasn't been accepted yet, I could still amend it...)
Anonymous