net-analyzer/munin writes some log files to /var/log/munin, and it should have a USE=logrotate that installs a logrotate script. Upstream bundles examples for Debian, i.e. ./munin-1.3.4/dists/debian/munin-*.logrotate
And we have contradiction with bug 198901. My opinion is that USE logrotate is good idea but we should add some eselect logrotate to enable/disable logrotate jobs. Never got there...
in 1.3.4-r2 rev 1.5.