I'm the author of Fulguris which is in conflict with Styx. Both projects are MPL 2.0. Fulguris is a fork of the decade old Lightning and Styx is just a rebrand of Fulguris. See also that other open source question.
In the future to prevent such abusive rebrands to fail to properly credit Fulguris and its contributors I want to make sure they have a legal requirement to prominently display something like: "Powered by Fulguris", hopefully making sure users of rebrands are aware of where they are coming from and who is actually providing them with the good stuff.
I'm considering using CPAL as it seems it was designed for that purpose. I'm also considering modifying MPL 2.0 by adding a badgeware close much like CPAL is a modification of an earlier MPL version.
I probably won't bother with a full relicensing as I would need to try get in touch with all 67 contributors which could be taking a while. Instead I'm thinking both license could live side by side as long as it is well defined to which files they apply. Any new file would fall under that new CPAL like license and I think I should also be able to relicense all existing files for which I have sole copyright.
Does that seems right to you? Any tips and advice are most welcome.