I wouldn't hold my breath on Firefox adding support for importing inside workers. I've personally worked around it with the convoluted solution of bundling modules with the in-browser version of esbuild immediately before playing (the use case being in-browser modular playgrounds and editable stuff such as this).
Some of the developers working on Firefox have told me that they are working on it. They've been taking their time to get it done, but the issues this depend on are showing progress. It should come eventually.
I'm hoping not to have to bundle things because it might be easier for users to report bugs that way, but if I have to I'll do it. esbuild looks nicely documented :)
