Today, when the deposit loader fails to ingest, it simply mark the deposit's status as
failed without any details.

It'd be great if it could also reference a more explicit error message. As a first
approximation, having the unexpected error message (of the technical exception) could be
enough.

The status_detail column (table deposit) is exactly meant for that. It's currently only
filled in by the checker process which does checks on the deposit prior to loading. If
that process detects errors, it marks the deposit as status rejected and gives some
status detail in that very column.

The end goal being helping in diagnosing faster the problem [1] both for client and
operation people.

[1] T3439