Spectre, Masterpassword. What's the difference?

The general idea behind masterpassword is to mathematically derive a unique password from a "master password". The idea and algorithm was published by Mr. Billemont as an open source MasterPasswordApp on iOS (android and others followed thereafter). The idea caught on and several compatible implementations emerged from various developers. typically because there was no app for their preferred environment. As is the reason for the existence of this project.

In 2021, Mr. Billemont re-released his app-efforts under a new name: Spectre. Spectre is still MasterPassword, just with another name, in other words just "another compatible implementation". Mr. Billemont sited among other things technical debt for motivation. I guess differentiation/branding could be added to that.

The important takeaway is that the masterpassword algorithm is free and licensed under GPL. The release of Spectre has no consequence for the algorithm, the masterpassword ecosystem or this browser addon.