optional prerequisites

figuring out how it works

Launch vim, type :help to open the help screen and use ctrl-w o to make it the only visible window
Now run :help restore-cursor, look at the source code, the dependencies to understanding it would be autocommands, autogroups, line(...), execute, use help to find out how they work
hint: know that \" escapes the " character so that you can put it inside of a string like: "'\"", which is the string that represents '"
Finding our way to the reference manual, open up motion.txt under basic editing, by placing our cursor on the file name and pressing ctrl-]
Next navigate to the mark-motion section of the file, scroll the window downward in the buffer a few times until you find '", now understand what it does.