How can I deploy direct from Google Cloud Source Repository to Google App Engine?

Google offers git -> App Engine and git <-> Source Repository, so presumably somewhere it offers Source Repository -> App Engine.

But I can't find where... even after twice reading all the Source Repository and App Engine docs I can find, inc. https://cloud.google.com/source-repositories/docs/ .

I'd guess the procedure could be How to manually deploy direct from Bitbucket to Google App Engine? modified to access the SR files. But I can find the SR files in the GCS VM.

Deleting all the $HOME folders I do find

... have no effect on the files shown at Source:

Baffled.

Solution