Stefan Beller [off-list ref] writes:
Occasionally a user is given an object hash from a blob as an error message
or other output (e.g. [1]).
It would be useful to get a further description of such a blob, such as
the (commit, path) tuple where this blob was introduced.
This implements the answer in builtin/describe,
however the heuristics are weak. See patch 6 for details.
Overall this was a relatively pleasant read. Will queue.
Thanks.