We are still solidifying patterns around how licenses should be managed, but given the Gemfile.lock file is ignored, I don't think it makes sense for linguist to track licenses for Ruby dependencies. A consumer of this gem could end up with a different version of a dependency that has a different license.
In general, I think libraries should only track licenses for code that they vendor. Since linguist vendors the grammars, it makes sense for it to track the licenses for them.
