F6 works in Internet Explorer, Chrome and Firefox. Whether it takes you there on the first press in all the browwsers I've mentioned is another question that I haven't investigated to any extent. But it is by now a standard command in many browsers.
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In every browser, at least all that I've used, the ALT+D command throws focus to the omnibox/address bar with the contents of same selected for copying.
F6 doing the same thing in Firefox seems to be a Firefox specific use of the F6 key.
Brian - Windows 10 Pro, 64-Bit, Version 1809, Build 17763
Growth for the sake of growth is the ideology of the cancer cell.
~ Edward Abbey