In T9924#147596, @epriestley wrote:

So - a technical team lead would encounter this.

I'd describe myself as this, at least approximately, but never have files lying around that I don't want to commit. Why wouldn't you want to commit a file?

One use case is indeed in the Java world (we're a Java shop). But support for this would also be really useful in situations where you're working on a feature (or several different features) orthogonally in different branches, and sometimes have uncommitted files lying around you don't want to commit just yet, and have to perform reviews on other people's code to boot. So - a technical team lead would encounter this.

Patch is currently here - we needed this in production so we wrote it and then looked at the contribution guide later.