Install the beta
CrosTem isn't on the Chrome Web Store yet. Until it is, installing the beta takes about a minute: download one file, flip one switch, pick one folder.
A .zip from the project's GitHub Releases — no installer, no account.
Download and unzip
Grab the .zip from the latest release and unzip it. Keep the folder somewhere it can stay — your browser reads the extension from there.
Open the extensions page
Copy the address below into the address bar and press Enter. On Brave or Edge, brave://extensions and edge://extensions work the same way.
Enable Developer mode
On that page, flip the Developer mode switch in the top-right corner. It unlocks loading extensions from a folder.
Load the extension
Click “Load unpacked” and select the folder you unzipped. The CrosTem icon appears next to the address bar — that's it.
You're set
Open any game on the Steam store and look for the “Runs on Mac?” panel in the right column.