> Have a 'Gecko' module, have an 'UI' module, have a 'telemetry' module, ..... this would allow people to build Firefox 'flavors' instead of forking everything.

> Have a 'Gecko' module, have an 'UI' module, have a 'telemetry' module, ..... this would allow people to build Firefox 'flavors' instead of forking everything. Everyone would contribute to the same project/ecosystem, users can discover the big project, and immediately download 'vanilla', but also get info on whatever flavors there are and in what way they differ? What is the real problem here? People are doing this. Brave and Edge are "Chrome flavors". See also https://servo.org/ https://servo.org/ or the npm and cargo ecosystems. That said interfaces are incredibly hard to get right. They take an unreasonable amount of work to make and will often end up being unsuitable or obsolete leading to a world of breakage, inefficiency and pain.