Re: proton. The reason why I'm quite sure that proton is running with similar setup to what l did in the past for product line development is their repository structure, most visible with their "common" set of libraries and then this is used across all their apps (there's one like this for android too.) They are basically creating products and generalizing ideas. When I first saw this I was wondering who from my old team leads went to work for proton - but turned out none! Arrogant me thinks good ideas never are unique.

This is also why I'm not using proton on secure devices because I tried for more than a year to review all the android stuff and it literally updates faster than I can review so it's a never ending story of being behind the development curve.

So proton is great. It's even open source. But it is not a good solution if you want to be in control of the code that runs on your (secure) device. Too complicated, too institutionalized. I did this in a closed source mixed hardware/software org; I'm not sure if the model really works for open source.