A common documentation file format that includes a list of changes between published (and sometimes unpublished) versions of software.
Debian packages have excellent changelogs. Here is an example of one, for the package of PerrysFirewallingScript that CraigBox maintains:
linuxserver-firewall (0.65) unstable; urgency=low * Add man page (thanks to John McPherson) * Update README.Debian to refer to documentation -- Craig Box <packages@wiki.example.org> Thu, 19 May 2005 10:45:33 +1200 linuxserver-firewall (0.64) unstable; urgency=low * Remove ()s from sourcing rules. -- Craig Box <packages@wiki.example.org> Mon, 9 May 2005 13:37:13 +1200 linuxserver-firewall (0.63) unstable; urgency=low * Set LANG=C in firewall.functions in order to work around bash accepting lower case letters in [A-Z]. Backed out some changes made to fix this. -- Craig Box <packages@wiki.example.org> Thu, 5 May 2005 14:00:10 +1200 linuxserver-firewall (0.62) unstable; urgency=low * Package for Ubuntu. -- Craig Box <packages@wiki.example.org> Thu, 5 May 2005 10:46:41 +1200 linuxserver-firewall (0.61) unstable; urgency=low * Fixed $CONFDIR in firewall.functions such that the per-if rules are loaded. * Set all rules executable. -- Craig Box <packages@wiki.example.org> Wed, 6 Apr 2005 11:42:04 +1200 linuxserver-firewall (0.6) unstable; urgency=low * Rebuild package due to loss of build source. -- Craig Box <packages@wiki.example.org> Mon, 4 Apr 2005 14:56:45 +1200 linuxserver-firewall (0.5-REL3) unstable; urgency=low * Updated to upstream REL3 version. * Hardcoded more details (bad) -- Craig Box <packages@wiki.example.org> Thu, 10 Jun 2004 11:47:25 +1200 linuxserver-firewall (0.3) unstable; urgency=low * Added support for TCP ECN disabling and IP accounting -- Craig Box <packages@wiki.example.org> Mon, 19 May 2003 19:40:53 +1200 linuxserver-firewall (0.2.2) unstable; urgency=low * Now sets +x correctly on rulesets (makes running the firewall much less painful) -- Craig Box <packages@wiki.example.org> Mon, 19 May 2003 19:33:07 +1200 linuxserver-firewall (0.2) unstable; urgency=low * Debian init script * Moved classes.d and interfaces.d into /etc -- Craig Box <packages@wiki.example.org> Mon, 5 May 2003 16:23:31 +1200 linuxserver-firewall (0.1-1) unstable; urgency=low * Initial Release. -- Craig Box <packages@wiki.example.org> Tue, 22 Apr 2003 04:32:24 +1200