Braus is new to me, tho at a glance looks less capable overall than Junction.
Looks like Junction supports firefox profiles via .desktop entries, so it would also support launching via the private CLI flag (firefox -private-window iirc).
Might be easier to keep up with than modding Braus source code in the long run.
https://github.com/sonnyp/Junction
Like other gnome circle apps it heavily encourages flatpak but its available on arch official and other distro package managers.
Speaking as an engineer doing a lot of web dev, I think people underestimate how much work Mozilla does in standards and low-level shared API’s via w3c and others, and how important it is that google isn’t the only one in there making decisions. Most w3c standards decisions are made with google, Mozilla, Microsoft, and apple representatives in committees, and as we know, two of those are much more aligned in their own best interests these days, while one kinda wishes mobile web browsing didn’t exist.
Would we have a better browser with less Mozilla baggage? Possibly.
Would the web standards that make everything work be better off without Mozilla? No, absolutely not.
Safari’s team does what they can within Apple’s bullshit intentional deprioritization of anything that could compete with the App Store, Edge’s team has brought some sanity to the chromium side and toned back some of Google’s wilder standards proposals and intentions. The fact that there are now 0 legitimate reasons for a website to “only work in chrome” (aside from some mobile safari things still) nowadays is all the stuff behind the scenes that matters. Even google is doing less FAFO shipping features and not caring about what other browsers need.
That said, maybe a disruptions is needed to a new paradigm could step in. Maybe a Mozilla Foundation placed under other ownership with a narrowed focus.
In the Linux space, the massive investments that GNOME, KDE, and others have been able to garner the last few years from governments and interested organizations is promising. There could be a similar interest in a web-focused org that could champion things without the Mozilla baggage and intent to avoid the same fate.