As for performance, Python 3.x was not even as fast as Python 2.x in the beginning, but with the correct mindset, it's eventually faster.

Do you mind elaborating on what features are missing?

Basically, there are 2 legislation in the world, legistlation and the China legislation. In China, there are laws on the surface and there are rules underneath. For example, the government never admitted that the GFW exists, yet it keeps blocking more and more sites. The government never bans online forums, yet it never grants license to open a online bbs, since like ten years ago.

During some political sensitive times, the government would send secret requirement to local companies like ByteDance and Tencent on how to censor the social media. Back when I worked at ByteDance, when the 19th Communist Party congress was open, the auditors would be in a war room, just for making sure that no negative news or comments would be released. American companies also work with the government on censorship, more or less, but that's another story.

It's very common for Chinese people who have been fooled by the government to say that, these western companys left by themselves. But it's not the laws that on the surface drives them away, it's the rules underneath.

You can find support for old firefox versions in the original repo.

The original repo was already full of hacks, and on top of that, I added more hacks to keep up with the latest browsers. The main purpose of my fork is to serve as a foundation of the python binding, which I think is easier to use. So I haven't tried to make the whole process more streamlined as long as it works on the CI. You can use the prebuilt binaries on the release page, though. I guess I should find some time to clean up the whole thing.