Depending on the impact of the change, contributing to open source software can be intensely challenging. Referring specifically to CPython, the reference implementation of my favorite programming language, you can have literally hundreds of messages on the mailing lists, and at times, many more in the issue tracking system, all discussing the change in mind. Such changes are most often accompanied with a PEP (Python Enhancement Proposal), a formalised document which is basically a design spec for the change in mind. It also, helpfully, summarises the arguments against the change, and addresses them while at it, which can be of help to those not inclined to consume the oft-lengthy discussions.
Given all that, it can be quite challenging for any one individual to champion such important changes, and an example of one such heroic individual is Victor Stinner, a core CPython developer. He is the most visible of the guys who helped ensure acceptance of PEP 418, which proposes some time-related additions and improvements to the standard library's time module. There are many such additions, many a lot more important than this specific one, but what's most unique about this one is the sheer amount of discussion that went around this particular PEP. The mailing list discussions were practically endless, and so were the updates to the PEP, not to mention the amount of research involved, which was needed in order to have CPython expose the new functionality in a cross-platform manner. Now, that's some serious perseverance.
Looking at his commits, the guy has done a heck of a lot of work in cleaning up, refactoring, and optimizing the string-handling code. I can't imagine that this stuff is easy, especially since a large portion of it is in C, that scary, no-hand-holding language.