Building on an idea he had since he was a child, security software engineer CTurt developed a way for people to play unofficial games on a PS2 console by burning them to a DVD to side of a feat.
If you are down for a very technical explanation of how it all works, please check out the CTurt blog. If you just want the tl version; dr, it basically created a way to “exploit the functionality of the console DVD player” by triggering corruption in video playback and then playing a game through the hole resulting in system copy protection.
Why is it important? Because all you have to do is insert a disc, the same way you would launch any other PS2 game. You don’t need to get a mod chip, you don’t need a special USB exploit, you just insert the disc and you can read new code without changing anything at the console.
CTurt’s blog post goes to great lengths to underline the word “homebrew”, but if you were wondering about more direct applications for this feat, two of its demo videos show a PS2 running an SNES emulator and a “backup” copy of The shadow of the colossus.
While this clearly works on a PS2, CTurt theorizes that the same feat (or at least the same principle) could also work on everything from a PS1 to a PS4.