Jeff King [off-list ref] writes:

quoted

I use it myself and I really hate the way it lists the patches.  We
should have done "log --oneline --reverse" instead of "shortlog", as
it is hard to understand the reference the cover letter message
makes to individual patches like "the first two patches do X", etc.

Agreed. I have long hated the shortlog version. According to the commit
history of my personal scripts, I've been sending with:

   [1/3]: subject of the first patch
   [2/3]: the second patch
   [3/3]: and so on

since at least 2009, and nobody has complained. ;)
...
But anyway, if this were happening internally in format-patch's
cover-letter code, it should be quite easy to do (we have the complete
list of patches and their subjects there already).

A good bite-sized #leftoverbits project for somebody relatively new
to the codebase, perhaps.

Thanks.