explain naming

[gajowi]

Tentative first PR from my fork. Since the change is so trivial and intended for upstream, I've just worked on the fork's master - and not varied the CI config to test the fork. Feel free to tell me if this is OK or not. I'm not sure what is best practice on this point

[paulfantom]

GitHub doesn't recommend working on base branch (in this case master), but that's mostly to allow easier synchronization with a repo from which fork originates. From my side there is no restrictions on the matter of which branch you are using on your fork :)