Could you clarify if you are looking for a to the game, or if you're interested in the technical details and code behind how it was recreated? game.html - RohanChacko/Subway-Surfers - GitHub
Today, if you search for "subway surfers githubio 2021," you will find archived Reddit threads, YouTube tutorials with broken links, and a few dedicated Discord servers sharing private, unlisted builds.
Most 2021 GitHub.io releases were not the official 2021 update. Instead, they were of the classic 2013–2016 era, tweaked to run on HTML5. Why? Because the old code was lighter. It didn't require constant internet verification, and it stripped away the modern "keys" and "event coins" that frustrated purists.