Those are probably inside the emacs info path, check this link out for more details
But basically, emacs uses either an environment variable INFOPATH (you can check this one using
echo $INFOPATH in the terminal) or, if the first isn't defined, a variable named
Info-default-directory-list in emacs. You can check the latter typing it in any buffer and pressing C-x C-e with the cursor after it. The folder will show up in the small message box in the bottom of the emacs window.
/usr/share/info, but I'm not sure if this changes in other distros.