possible fuzziness for b4 trailers -u?

Hi,

I sometimes run b4 trailers -u to collect tags on patches that have been
meanwhile slightly modified in git since the posting. Sometimes it's on the
b4/$cover_topic branch as a submitter, sometimes it's already applied (but
not stable as in no history rewrite) on a maintainer tree branch (I do use
--since-commit and doublecheck the result of the update closely since some
past surprises...).

AFAICS the trailers update relies only patch-id (?) so it will miss the tags
when patch-id changes due to these local modifications. Could it try some
fuzzy matching in that case? Some ideas:

- in b4/$cover_topic branch the metadata allows finding the posting thread
and matching the patch subject
  - ok, subject can sometimes change too, but not so often as the code

- in maintainer tree branch, there's usually a patch.msgid.link Link: that
can lead to the given patch rather deterministically.

Thanks for consideration!
Vlastimil