What do those do?

^w is delete word in vim/bash/everywhere else. It’s terrible whenever I accidentally type this in the browser and the window closes. I typically close terminal windows with ctrl-d so I have this mapped in my browser as well. It’s really muscle memory and I do not want to change it

By that same logic, ^w is used as close window everywhere else

Not for me, I hardly use anything GUI apart from my browser. Can’t actually think of anything right now apart from some niche tools. Either way, the fact that I can customise it that easily in Chrome but not in Firefox is a huge factor why I don’t like using Firefox

Not in Windows (pun unintended) where it works only in Explorer.

Patch localization/en-US/browser/browserSets.ftl in your browser/omni.ja (a .zip with a weird file extension), it contains stuff like: close-shortcut = .key = W

See: https://github.com/SebastianSimon/firefox-omni-tweaks how it can be done.

I do this myself as ctrl-n has to be new tab for me, forever, and firefox broke the old keyconfig extension years and years ago. (I had ctrl-n create tabs with an external window manager back in netscape 4 times and opera (pre-chrome-fork one) after that.)

Amazing, thank you!