The list you linked is for games with native ports to Linux, not the ones you can run through proton. But dozens of others already pointed you to it, check it out sometime.
Basically, a playbook is a set of instructions or baselines for how you want the system to look/be setup, and the provisioning tool will engage in however many tasks are required to configure the system to your specifications.
lol, what? the british just returned lands they stole, after a century's worth of exploitaition