> My question to the FOSS community is why Firefox is not used to build more independent browsers the way Chrome is?
I actually looked into this. Say you consider yourself as part of the FOSS community, and want to build a new browser, and you start to look for your options. The only things readily available as libraries are webkit (currently owned and open sourced by Apple) and webkit-gtk (based on the former). Apple is like Apple and doesn't really want you to use their open source lib, so even though webkit-gtk team made it happen anyway, good luck if you want to do it yourself. If you decide to just use webkit-gtk, you've made a decision similar to lots of other members of the FOSS community in this area (luakit, the Rust webview crate, etc.). Another option is Qt WebEngine. It's based on Chromium. It's part of the Qt ecosystem and though I think you can use it as a standalone library, carving it out still requires some engineering. So these are the options that are available as libraries. And where are the Firefox ones? Servo makes it clear at the beginning of The Servo Book that it isn't available as a library yet. And Gecko? Firefox source doesn't even include a directory named gecko. It's so tightly coupled with the other parts that you'll need a lot of engineering to carve it out. And this is in contrast to Blink, the engine of Chromium, which is nicely placed in its own directory, having its own webpage with some learning resources.