Comment by seanhunter

That's actually an unfortunate side-effect of banks having weird requirements. When I was at GS we had this enormous source repo built on CVS. So we made improvements to CVS to try to make this more manageable . For example because branching in CVS absolutely sucks we had to use tags (rather than branches) to identify releases. This meant you end up with lots of tags and when you look at them it's really hard to find (visually) whether code has a particular tag. So we patched CVS to sort the tags alphabetically. We tried to upstream this but the CVS devs didn't want to know. So we had to maintain it.

Likewise a bunch of fixes to the timezone handling code that iirc glibc simply wouldn't upstream so we had to maintain even though they were bugfixes.

We did used to upstream everything we could and I think the situation is improving.