I've heard back from the original author and he says his icons are
public domain and I can use any licence I like. I think it would be best
if I stick to CC-BY and update the metadata and copyright file.
- Bug#795217: missing license in debian/copyright Thorsten Alteholz
- Bug#795217: missing license in debian/copyright Tony Houghton
- Bug#795217: missing license in debian/copyright Thorsten Alteholz
- Bug#795217: missing license in debian/copyr... Tony Houghton