Change 214075 abandoned by Mattflaschen:
Add extension.json, empty php entry point
Patches of this nature (no super-urgency, applies to both master and release branches) *must* be merged to master first.
extension.json changes don't need to be specially put on the release branch at all. If they did, you would use the cherry-pick button on Gerrit after the master one was merged. If that failed, you would use git cherry-pick on the command-line and fix the conflicts.