F9 doesn't seem to do anything for me on Linux... Neither on the posted page nor on HN.
What is it supposed to do?
There is no mention of F9 on this support page either:
https://support.mozilla.org/en-US/kb/keyboard-shortcuts-perf...
Am I missing something?
I assume they are trying to enable Reader mode which is Ctrl+Alt+R
yeah reader mode it is, didn't know it's different on Linux than on Windows and the support article listing it is here: https://support.mozilla.org/en-US/kb/keyboard-shortcuts-perf...