[flohofwoe]

Looks like in Firefox v56 you need to change the start page to "blank" in the preferences (edit: to get the address bar focused after opening a window).

However in current Nightly (which is on v58) the input focus goes straight to the address bar, even in the default settings, so looks like more users complained ;)

I'm just using Ctrl-L to focus the address bar, works on all operating systems and browsers.

[mariusmg]

Alt +D. Left hand friendly :)

[jhasse]

Opens the File (german: Datei) menu with German Firefox.

[vram22]

Didn't know that. It's handy. Thank you :)

[whoisthemachine]

F6 works as well in all OS's I've used (Linux Mint and Windows).

[fiatjaf]

On Firefox 57 that is indeed solved.