You know, it would be cool if there were some kind of open source project to develop a cross-platform web browser for legacy and vintage operating systems with support for modern web standards and protocols, but which could be compiled to run on older 32-bit operating systems, including old Windows NT versions and perhaps even Windows 3.x with Win32S. Or heck, even in DOS, using a 32-bit DOS extender, a mouse driver, VBE graphics modes and optionally sound support. Obviously some stuff such as WebGL wouldn't be possible, but a lot of other stuff (including up-to-date TLS versions and even JavaScript support) could be made to work. 🙂
A highly portable 32-bit web browser with minimal requirements (a graphics mode, a mouse pointer and a TCP/IP stack). With a cross-platform and endian-neutral code base that allows it to be compiled even with older compilers.
Basically the same idea as TenFourFox, but cross-platform. It would require quite a bit of backporting work, though. Pretty much the only two remaining open source browser code bases are Firefox and Chromium, both of which use modern language features (and in the case of Firefox even require a Rust compiler), which aren't available in older environments.
Perhaps TenFourFox could provide a good basis for it. The single developer who has maintained it over the years (and recently announced he will stop developing it) has done an amazing job keeping that Firefox fork working on old versions of Mac OS X on the PowerPC architecture. Maintaining and optimizing the JavaScript browser alone has been quite an impressive effort. Much of it PowerPC-specific, but still, a much better starting point, I think.