Patrick Steinhardt [off-list ref] writes:

I think the porcelain mode is already built so that it can be extended
with arbitrary new information, no? In `emit_one_suspect_detail()` we
end up printing one line per info we want to display. I would have
expected that we can extend that function to also print information
around unblamable or ignored commits, like we already do for boundary
commits. E.g. something like the patch further down.

Yeah, I think the porcelain format exists to be easy to machine-parse.
Having an optional prefix symbol on the commit OID would complicate
process that.

And I've been thinking about a similar solution as you've been
suggesting below. I was only wondering whether we only do this when
using `--line-porcelain`. When using `--porcelain` the function
`emit_one_suspect_detail()` doesn't print most of the commit info when
it was already printed. But the "unblamable" and "ignored" info might be
different for each line, even if they blame down to the same commit.

-- 
Toon