Someone from FB did a really cringe-inducing presentation a few years ago about how "X can't handle our scale" (I think the predicate was iOS, but they went into IDEs and SCM systems). They had to pull the video and slides because it was so bad.
Facebook patched Android Dalvik to increase the "max methods per app" limit.
Don't know if there's a similar iOs story.
They're whole schtick was "we're Facebook and we have unique scaling needs that no one else does," which makes absolutely no sense from the perspective of one user's content being rendered on their phone.
Plus the presenter was pretty smug, like all of this was good, when he wasn't convincing anyone that it was even necessary.
Found the slides: https://www.columbia.edu/~ng2573/zuggybuggy_is_2scale4ios.pd...