K Jayatheerth [off-list ref] writes:

Subject: Re: [GSOC][PATCH v2] Remove outdated mentoring mailing list reference

[Documentation/SubmittingPatches]

    The first line of the commit message should be a short description (50
    characters is the soft limit, see DISCUSSION in linkgit:git-commit[1]),
    and should skip the full stop.  It is also conventional in most cases to
    prefix the first line with "area: " where the area is a filename or
    identifier for the general area of the code being modified, e.g.

    * doc: clarify distinction between sign-off and pgp-signing
    * githooks.txt: improve the intro section

    If in doubt which identifier to use, run `git log --no-merges` on the
    files you are modifying to see the current conventions.

and clarify tutorial prerequisites

Do not do this.  What you have on the e-mail "Subject:" line is the
first paragraph (whose definition is block of text delineated by
blank lines) of the commit log message, and the first paratraph in
the body of a patch e-mail is the second paragraph.  You do not
start your second paragraph at half-sentence, as if it were a
continuation of an incomplete previous sentence.