O.S.I.R -- Firefox Bafflement Edition

Ohhhhhkaaaayyyyy....this makes sense:
(Using Firefox 39)

Ctrl+Shift+Q brings up a new tab and loads Youtube.
Ctrl+Shift+W shuts firefox down,
and Ctrl+Shift+G loads the 'Find text in tab" searchbox.
Now how is Ctrl+Shift+G a better combination than Ctrl+F ? (Which also works just fine)
And what is the G a mnemonic for? (It better not be grep, 'nixheads)
So what was wrong with Alt+F4 that needed Ctrl+Shift+W to replace it?

The googles claim that Ctrl+Shift+Q should bring up Foxclock addon Zone Picker, or the Network Monitor, depending on your Kool-Aid taste of the day, I guess.Why Youtube?


....oh and now my URL is right-justified. Why? How? Why would right justification ever be needed in a URL bar?