> If the functionality has been removed from neovim, then why should neovim claim that a bug in that functionality is fixed?

For example, Vim 7.4.164 fixes a bug in `os_win32.c`. It doesn't make sense to apply this patch because we defer to libuv for system functions; but it also doesn't make sense to say "this bug wasn't fixed". The functionality does exist in neovim, but the implementation was changed such that the bug fix is obviated.

> If the functionality has been reimplemented, and the bug can't be reproduced, then I could see adding an indication that the patch has been applied,

I think we all agree with that.