Looking for a professional free open source Screendesign tool that doesn’t lock you into subscriptions or fees but offers the full range of features? Penpot has you covered. I ran into this a few years ago but finally had the change to play around with it. And I’m impressed.
Penpot runs as a JVM Applikation built with Closure and ClosureScript, but there is an official preconfectioned Docker image to run it locally, much like a regular desktop applikation, only that you call it in your browser. Works for me.