Semi-colon at beginning of first line in commit log?

[Eli Zaretskii]

What are all those semi-colons in the logs, like in the messages
below?

There's nothing in CONTRIBUTE about that, and they get in the way when
reading the log.  Why do some people use them, and then only sometimes?

  commit 937b22fe461922329b9ae13a6148c29ff8263f2a
  Author: Glenn Morris <address@hidden>
  Date:   Tue Apr 21 17:56:29 2015 -0400

      ; ChangeLog fix

      Reposition local-variables to where most ChangeLogs seem to keep them.
      Also helps gitlog-to-emacslog.

  commit f5076daca0c640cd53b2fb71ab693db3c83ad020
  Author: Vibhav Pant <address@hidden>
  Date:   Mon Apr 20 00:17:31 2015 +0530

      ; * etc/NEWS: Add "+++" to eshell entry.

  commit 870287327b1fba7105599eeabac5a2aa5ebadf19
  Author: Paul Eggert <address@hidden>
  Date:   Sat Apr 18 19:45:38 2015 -0700

      ; Convert ChangeLog history files to "Bug#NNNN"

  commit b06b46e280f3772c62c207e73d87c58b78f42119
  Author: Simen Heggestoyl <address@hidden>
  Date:   Sat Apr 18 20:06:48 2015 +0200

      ; ChangeLog fix