Very customizable, however as other users have already pointed out you have to change some entries in about:config if you want it to work with the alt key (otherwise you can use the "right click + scroll" option instead) and you have to enable the "access data for all websites" permission for it to work on all websites right away. Being able to reset the zoom with alt + middle click is a great feature

The Chrome version works great in that browser, but this Firefox version simply does not work at all.

Great idea but it doesn't work perfectly.

## Alt Key Problem

Using the Alt key is terrible. As alixyz pointed out, pressing Alt combined with scrolling still opens the menu bar (about:config > ui.key.menuAccessKeyFocuses). Also it overrides the default Alt + Scroll wheel functionality. Usually you can go back and forwards with Alt + Scroll wheel. That's not possible anymore.

You can use one of the other options, but mouse button + scroll whell is a really strange key combination. Usually shortcuts involve keyboard buttons, you don't really ever have a key combination consisting of multiple mouse buttons.

It would be great if you could pick a custom key. For example Shift seems to work fine and doesn't create any problems.

## Permissions Problem

I had another problem with the extension's permissions. I had to go into the extension settings manually and give it permission to access data on all sites. You should get a pop-up where the extension asks for permission and you can simply click yes.

99% of the people wouldn't know that there's an option in the extension settings and that they have to give that permission manually. If you don't do that in advance, you need to first click the extension on the toolbar every time you visit a different site to make it work. You can also right click the extension and click "always allow on that page". But that's not very useful either. You had to do that on all websites you visit.

## Sticky Headers Problem

There's another problem. It probably has to do with sticky headers since that's already addressed in the extension settings. When I zoom in and out on Google Search, it changes the position of the search bar and moves it horizontally more towards the center. It's not at its default position anymore. I also saw that one time the search bar was randomly shown in the middle of the screen when I was zoomed in. I don't know why this happens. It seem like this extension doesn't use the exact same technique that Firefox uses when zooming with the touch pad. Maybe we should research on how Firefox does it and copy that exact behavior.

Works enough to use, but there are bugs.
Remember to enable site permissions to use everywhere.
If you want alt+scroll to work without triggering other actions, change about:config settings ui.key.menuAccessKeyFocuses to false (to avoid menu trigger on alt) and mousewheel.with_alt.action to 0 (to disable back/forward actions on alt+scroll).

It's just too buggy.