Firefox does not have a built-in feature to disable keyboard shortcuts (with very rare exceptions).

Is the problem that a page that uses Ctrl+H isn't working as expected?

If you just want Ctrl+H to do nothing, maybe one of these add-ons can do it (I don't use these myself):

• https://addons.mozilla.org/firefox/addon/saka-key/
• https://addons.mozilla.org/firefox/addon/shortkeys/

Is the problem that a page that uses Ctrl+H isn't working as expected?

Oh, it is working as expected. But every time I hit Ctrl + H is accidental. :) In other words, I don't intend to do Ctrl+H.

If you just want Ctrl+H to do nothing, maybe one of these add-ons can do it (I don't use these myself):

• https://addons.mozilla.org/firefox/addon/saka-key/
• https://addons.mozilla.org/firefox/addon/shortkeys/

I guess I could install another extension, but I try to be minimal in my use of addons, especially if tweaking some file in the Firefox code would do the job. :)

If you are into advanced hacking, a startup script can remap keyboard shortcuts. I have a general page on that, but r/FirefoxCSS would be a good place to get a specific recommendation:

• https://www.userchrome.org/what-is-userchrome-js.html
• https://www.reddit.com/r/FirefoxCSS/

This is about the key command with ID "key_gotoHistory".

• https://searchfox.org/mozilla-release/source/browser/base/content/browser-sets.inc#279

See this thread for code you can use with autoconfig.js and autoconfig.cfg.

• /questions/1376993 Key binds

See this thread for code you can use with autoconfig.js and autoconfig.cfg.

• /questions/1376993 Key binds

Dear cor-el, I found your reply in this "key binds" post that mentions autoconfig.js and autoconfig.cfg: https://support.mozilla.org/en-US/questions/1376993#answer-1505522

Steps to disable or enable Ctrl key shortcuts in CMD on Windows 10:

I'm on Linux. :)