It technically works, but needs a lot of improvement to be usable.

The minimum scroll speed is way faster than I can read. I'd need it to be able to go down to maybe 20-25% of that speed.

Middle clicking on a link should open it. Instead, it turns on autoscroll.

The icons are intrusive. The one that shows up and sticks on the screen when you middle click is way too big, while the one that sticks to your cursor is also annoying. Neither of those are necessary at all.

Optimally there wouldn't be any on-screen icons or there would be a toggle to disable them, but if that's not possible, they should at least be smaller and less intrusive. Chrome in Windows does a decent job of handling the icons, but I've never seen another autoscroll that doesn't look awful.

Edit: I just found out that Firefox has built-in autoscroll, but it's disabled by default for some reason. It works fine. Unless this extension receives some major updates, just use that instead.