Could you provide more detailed description?
As for me, mine still works in my Chrome as usual
Regarding Firefox: to use it as normal extension, developer (me) has to sign it and publish it in official store (cannot do that for now). To install from plain ZIP, you need to use Firefox Developer Edition and go thro mini-quest adding it. I did run it and continue to use Chrome as default browser, so no idea for now, sorry.
First of all, sorry for replying so late. A bunch of things happened, so my priority was focused to sorting that mess out further.
I allowed myself for some couple of hours trying to get things working, and tried backtracking to the latest version of chrome, where the sugarcube/twine hacker would work again. To make things quicker, I decided to look up the Dev Updates and documentations of different versions from both Twine and the Chrome Browser... and man, in this instance, guessing blindly would have been smarter and faster.
Skip this, because there is now rage ahead: Twines documentations are all over the place like the bodys of russian political opposition figures, after many of them fell numerous times out of windows from the highest floor. First they used a very detailled and practical github system on their wiki, which was continued only until dec 31st of 2020 (happy new year?), but where the last documentation of their updates was on the Twine 2.3.5 edition of Oct 8th 2019. Then it turns out, they continued the wiki on another website because it would be better because "more successful" and it's called... Cookbook. Fine, whatever, not my cup of tea but whoever named the website certainly has to be forbidden of naming his children. You may be a fine human being, but please, accept your flaws and let your partner name them. So, one quick look at the documentation of the new website, got a headache and started to think I was going mad or did something wrong. But nope. I was fine, not smarter or dumber than before, but the new site was atrocious for documentational purposes only. The other stuff on Twines Cookbook is fine from the quick peak I got. But come on. The latest documentation was from the Twine 2.3.8 version (rel.date:10.05.2020) - but no detailled github reference NOR a date given. We are at Twine v.2.3.11. Fine, fuck me I guess, had to now search for a date to pinpoint if the fault lays with Chrome or Twine and maybe get a fix for it or at least an idea. Turns out, all this research was useless, since Twine is definetly not at fault here, because between Twine v.2.3.9(rel.date:13.07.2020) and v.2.3.10(rel.date:03.01.2021) the only thing that changed were chrome and chrome based browsers. Since the first of us got the problem around november of the cursed year, things got changed around on the browser side of things. I was really happy! The happiest guy with the happiest thoughts, trust me!
So, after my dumbass finally realized that, I shut my pc down, laid down, cried and tried to not to kill myself again. Then I got up forgott about it aaaaand remembered that I now had to either find something to fix this issue with the help of documentations, or to blindly guess and try different old versions of chrome. I did the latter, beacause while I enjoy the community here, I really don't wan't to be the person in the news who ridiculously killed himself over documentations, trying to find a way to fix a non functioning hacker for... smut games. But. I am kinda retarded, and still looked into the documentations, because I wanted to know the reason, what caused this mess. Turned Google was very busy in november of the cursed year and released Chrome version 86.x to 88.0.4324.11. So, congrats to them, at least they weren't lazy. Take away: many "bug fixes" and even more security paches. And one of those latter broke the sugarcube/Twine hacker. If you have read until this point , thank you, you beautiful human being and thanks for listening to my small rant.
Tl;dr.: So the takeaway since I hardly am able to make sense of the security patches and don't know what exactly was done, use a chrome browser of the version 86.0.4240.198 (rel.date:Wednesday, November 11, 2020) OR LOWER!
Be advised, that you will have to go lower, since on my pc the 86.0.4240.198 worked well with the sugarcube/Twine hacker while on my notebook I had to use the one version before that.
I hope I could help some of you, have a nice one.
Oh and for the firefox approach, what Lure of Chaos said.
