Changing the space bar behavior to not page down upon key press would be immensely helpful. I understand that not everyone would appreciate being able to disable the current space bar behavior, but to me it would finally solve a long standing issue I've had with my workflow.
I often hit the space bar by accident, and wind up losing my place where I was reading online. I find it so frustrating to lose the sentence I was reading because of this, that I've taken to researching if any custom scripts exist for Firefox to disable the paging down behavior. Some do exist, but none have worked for me. There's nothing as well about:config.
That is why I'm glad to have the option to suggest directly that an option to disable the "space bar = page down" behavior would be very helpful. I hope it would be a small deal to fix that would lead at last to a lot of joy and relief. ☘️