I recently migrated from Chrome to Firefox and had been missing the ability to use backspace to back to the previous page. It occurred to me that there might be a Firefox extension and this one seems to work well for me. Now that I think about it, I probably had to install an extension for it to work in the latest incarnations of Chrome - it's just been so long that I added it that I didn't remember doing it.

Works well in most cases, but it's unreliable in YouTube where I want to use it most (to return to the home page after watching a video). I find after opening a video, whether it is playing or not, and regardless of where I click on the page, mostly it doesn't go back. It does occasionally, which, as a commercial software engineer myself, I know is the most infuriating type of bug. So mentioning it here in the hope that it may be useful to the dev to be able to attempt to reproduce.

The plugin is great and compact. For some reasons it doesn't work with GitHub (although history is present and works when pressing back icon)