From [1]: UnusedLicenseReport: unused license(s): CC-BY-ND-2.5, DSL, ECL-2.0, ODbL-1.0, intel-psb, mongrel, newton, urbanterror-4.1-maps Not sure about the generic licenses (CC) but i think we should remove the others. [1]:https://travis-ci.org/mgorny/gentoo-portage-rsync-mirror/jobs/50643306#L1392
Confirmed by own script (which I run roughly once per month). My approach so far was to keep everything that is widespread enough to have FSF or OSI approval. This is of course open for discussion: CC-BY-ND-2.5 DSL ECL-2.0 ODbL-1.0 These ones I have removed: intel-psb mongrel newton urbanterror-4.1-maps
Closing. For the time being, FSF and OSI approved licenses will be kept even if they are currently not used by any package.