Linux Mint Cinnamon 18 - In what file are the keyboard shortcuts saved?

You can utilize the following to export your keyboard shortcuts to a file:

$ dconf dump /org/cinnamon/desktop/keybindings/ > dconf-settings.conf

This requires the dconf-cli package to be installed. Then, to import the file after making any desired keybinding changes:

$ dconf load /org/cinnamon/desktop/keybindings/ < dconf-settings.conf