Fixing determination of branch For some reason, AppVeyor offers a APPVEYOR_PULL_REQUEST_HEAD_REPO_BRANCH variable, but that isn't set (for whatever reason). Contrary to its own documentation APPVEYOR_REPO_BRANCH points towards the source of a merge request, so that one is inspected as well.
Fixing determination of branch
For some reason, AppVeyor offers a APPVEYOR_PULL_REQUEST_HEAD_REPO_BRANCH variable, but that isn't set (for whatever reason). Contrary to its own documentation APPVEYOR_REPO_BRANCH points towards the source of a merge request, so that one is inspected as well.

Kittyfisto/SharpTail,Kittyfisto/Tailviewer