How do you exit vimdiff mode in vim, specifically, for Fugitive?

I had no luck with diffoff, but I just learned that :Gedit with no argument will bring you back to the working-directory version of the file, as opposed to some earlier version you were reviewing.

And as q (no need for :q) will close the diff sidebar, you can do q followed by :Gedit to get rid of the sidebar and then go back to the current version of the file.

You can execute windo set nodiff noscrollbind and then close the second window.

Update: there is a diffoff command. Use windo diffoff, not what I wrote in previous line.

According to: https://github.com/tpope/vim-fugitive/issues/36

Close the other window. The easiest way to do this if you haven't shifted focus to it is <C-W><C-O>, which means "make this Window the Only window."