Firefox, flatpak, reveal.js, and local file system permissions

I have installed the flatpak version of Firefox, which is far more up to date than the ESR version in Debian’s repos.

To load a file from a local directory (e.g. a .html file created using reveal.js), I needed to give it permission to access the directory. I decided to give it permission to my /home directory:

flatpak override org.mozilla.firefox --filesystem=/home/neil/

And I restarted Firefox.