Looks like the second vsprintf definition should be "BANNED(vsprintf)", not "BANNED(sprintf)". Not that it matters much, as it only affects the error message.
However, if you're more comfortable using GitHub PRs, there's a gateway interface at https://gitgitgadget.github.io/.
> Git Source Code Mirror - This is a publish-only repository and all pull requests are ignored. Please follow https://github.com/git/git/blob/master/Documentation/Submitt... procedure for any of your improvements.
I sort of get not allowing it, except that it's inconsistent.
If it is specific to one implementation, then it is not standard, pretty much by definition.