dubious missing license entry

[Fantu]

Hi, I spotted I dubious missing license entry in a fork of this ( mint-x-icons - https://github.com/linuxmint/mint-x-icons/issues/198 ) working on package inclusion in debian There is only GPL-3 license specified but I saw also "creative common" license in near one thousand icon files but I didn't find what specific license it is exactly, I suppose can be CC-BY-SA-4 or CC-BY-SA-3 which are common but it should be specified somewhere because there is also CC BY-SA 1.0 that is not a DFSG license compatible ( https://wiki.debian.org/DFSGLicenses ) Thanks for any reply and sorry for my bad english