Firefox: 92
Desired font: Monaco

Monaco is a mono font. But the addon isn't working. Instead, the default font attributes in the Firefox settings panel are observed.
To be clear,this is about the code font, not the markdown font.

I think this extension worked on GitHub gists also earlier.

suddenly I am seeing this is not working on GitHub gists.

I already have a developer account in the chrome webstore so I can publish this one on my account for you, of course, I would give you all the credits. Let me know if you're interested.
You can check out my extension on the store here:
https://virejdasani.github.io/virej/software/extensions

https://github.com/ceoshikhar/better-github#demo

I am a firefox user. I installed the extension from firefox add ons.

I had applied Fira Code and size 14.

Everything was heavenly until this happened.

When I am editing text in Github's editor, when the extension is enabled, the mouse cursor is not falling on place. If I click at a place, the cursor is falling far away from it.

If I click reset in the extension, then font changes to normal, and the cursor bug goes away.

screenshot from telewater