ref: dd027e1e5379019bfeffc48ff1274b5e05581ff3 dir: /format/pack/ingest/testdata/fixtures/sha1/METADATA.txt/
format=sha1 head=200c960359dad025b4170284c518919eb4a24305 base=4bc507fc631ea78474d83c47548743c9f1dda0dc