The figure on most keyboards is G. Yet when you press it, it puts on the screen, g. Chromebooks are better in this way. Their keyboards are labeled in lowercase.
I actually went back and forth between saying Shift-G, or just G, for this very reason. So I erred on the side of clarity.
In some contexts :help notates things as characters (ex zh, zH, and z<CR>). In other cases I'm seeing things written as <S-F11> and <C-G>. There's also CTRL-H (instead of <C-H>) but I'm not seeing shift written out like that for whatever reason. Sometimes they get mixed (I'm not sure what the rules are) such as for hh<Space> and hh<C-]>. Amusingly enough, :help appears to treat Meta-{char} as case sensitive but CTRL-{char} as case insensitive (I assume there's a reason). I also spotted a <kPlus> (for the keypad).
What an amusingly pointless distraction!