Nobody at Microsoft stood on a stage and announced the Mythic Achievement. Instead, someone went digging through the guts of the latest Xbox app on Windows 11 and found the icon, the unlock chime, and a chunk of backend logic sitting there unannounced, which is the modern way platform holders reveal features now: leave the assets in a build and let the internet do the marketing for free.

The find comes via Windows Central, which cites a tweet showing the badge, the plus symbol, and the unlock sound pulled straight from the app's files. The outlet credits the deeper technical breakdown to XCT.live, who apparently spent enough time in code nobody was meant to see to work out how the thing actually counts.

What the Datamining Actually Shows

Here's the part that should temper anyone already picturing a 100% Gamerscore flex. According to XCT.live's findings as reported by Windows Central, the app doesn't tally Gamerscore at all. It groups achievements into a bucket it internally calls BaseGame, and the unlock toast reads along the lines of clearing every achievement in the original game, not the game plus every DLC pack bolted onto it since. Anything outside that BaseGame group gets tagged as an Add-on, filtered out of what's required, and quietly excluded from the count.

So the 'completionist' badge people assumed would mirror the Platinum Trophy's everything-or-nothing math is actually counting achievements, not points, and only the achievements that shipped with the base release. A game that added a pile of post-launch DLC achievements won't force you to chase them for the badge (fine by anyone who skipped the season pass), but it also means the definition of 'complete' here is doing some quiet, undisclosed narrowing that Microsoft hasn't explained in public.

Corroborated, Not Confirmed

A second account of the same discovery surfaced on YouTube from Kaiser Ryu, whose video treats the badge as effectively arrived, while its description raises the obvious follow-up question: what happens to everyone who already finished a game's achievement list before Mythic existed. That's a fair ask, and Windows Central raises the identical hope for retroactive credit. Neither outlet has anything from Microsoft confirming it, because Microsoft hasn't said a word. This is two accounts of the same code leak, not two confirmations of a shipped feature, and that distinction matters more than the shiny icon does.

The site's own earlier reporting flagged this as an insider claim back on September 19th, and four days later the claim has grown a badge and a sound file but still no press release. Test the achievement list on your own completed games once this actually ships, because right now the only thing confirmed is that the assets exist. Whether the requirements holding them up survive contact with an actual launch is still Microsoft's call to make.