Subject: svlogd, when rotating, sets the log files as executable. Why?
From: Jamie Heilman <jamie@audible.transient.net>
Date: Mon, 8 Feb 2016 06:12:27 +0000

  This is all based off daemontools' multilog ...

  https://cr.yp.to/daemontools/multilog.html

  ... which states:

    While multilog is running, current has mode 644. If multilog sees
    the end of stdin, it writes current safely to disk, and sets the
    mode of current to 744. When it restarts, it sets the mode of
    current back to 644 and continues writing new lines.

    When multilog decides that current is big enough, it writes current
    safely to disk, sets the mode of current to 744, and renames current
    as an old log file.

  Thus it's effectively using the mode bits as flag to communicate the
  state of the application, which while unusual, is harmless.