That is, um, incredibly not clear, based on the link you shared.

'Proton is a tool for use with the Steam client which allows games which are exclusive to Windows to run on the Linux operating system. It uses Wine to facilitate this.'

Even reading down the article to look for more details provides information about building the product, but as far as I can see no other significant details about it's underlying technology.

There may be other articles or posts that go over this more, but your link provided no useful or helpful information that I could see in two brief read-overs.