A trip to a Scottish second-hand flea market has resulted in a stunning discovery: a 360 dev kit previously owned by Grand Theft Auto developer Rockstar Games complete with an early beta build of GTA 4.

At first, Jan, the person who found it, wasn’t entirely sure what he’d found, only recognizing it as a “Phat Xbox 360.” When he looked a little closer, though, he saw the Rockstar Games sticker, and then the ‘Sidecar,’ the expansion device attached to the side.

“I go to car boot sales quite often, partly to get stuff to resell and partly to get stuff for my personal collection,” Jan told Kotaku. “When doing my rounds, I saw what I immediately recognised as a Phat Xbox 360, with what I first thought looked like a ‘tumor’ sticking out of it, later turning out to be the Sidecar.

Every Celebrity in GTA 4

“I wasn’t entirely sure what it was, but I knew it was something good, so I asked the guy [how much], and he said five pounds [around $6.50]. I asked if he had change, gave him a tenner [around $13].”

It was only later when he got home that he realized what he had bought. Since then, Jan has shared the contents of the device online, and dataminers and tech experts are working to get it running. He also tried to sell the device — which reportedly doesn’t contain any other files or games — and despite receiving a £1,000 ($1,300) offer and listing it on eBay for $800, the auction was removed due to the dev kit’s software, so he’s now accepting private offers.

As for what the dev kit contains? Well, as one fan said, “HOLY. S**t. Something big has dropped.”

Interestingly, the 2007 build is “partially wiped,” although people cleverer than I am have managed to “retrieve most of the files,” including beta model images of the characters, weapons, items, vehicles, maps, and more, helping fans collectively work out what changed between this early build and the final retail release version. There have already been some incredible discoveries, such as the ferry that was seemingly cut after an early trailer, leading some to joke: “can’t wait to have the Ferry as a drivable boat.”

Hicieron funcionar el Ferry finalmente en la version beta de GTA IV!
El juego se crasheo cuando el usuario quiso spawnear un vehiculo en el Ferry en el primer intento. Luego probo de vuelta y le bajaron los FPS y nuevamente crasheo.
Que gran laburo esta haciendo la comunidad de… pic.twitter.com/XJ8K0acu9G

— Carrero (@carrerovYT) March 30, 2026

Early map design of Liberty City found in the beta build via DOUGL4S1

Source: https://t.co/ptZ50SaLS3 pic.twitter.com/O9T2BPF011

— ben (@videotechuk_) March 31, 2026

“My jaw is on the floor… This isn’t some late build, this is VERY beta. Like half of the radio stations are completely different…” exclaimed one such fan, while another shared what they believe to be evidence of an abandoned “zombie minigame.” We even have early versions of cut-scenes popping up online, too — some from previously unseen perspectives — and most recently, some have been able to get executable files to run playable, if broken, sections.

“Today has literally been a dream come true to me lol,” wrote one fan. “Can’t wait to have some more free time to spend an entire day combing over these files to find some random s**t that was changed.”

Ya lograron meter varios assets de la beta de GTA IV dentro del juego:

– El Ferry cancelado que aparece en el Trailer 1, que iba a tener un uso, pero fue recortado en la version final
– Varias armas, como la M4 version beta, y la pistola con silenciador
– Una camara entre las… pic.twitter.com/FoFxv0n8Xg

— Carrero (@carrerovYT) March 30, 2026

If nothing else, this’ll keep GTA fans busy while we wait for GTA 6, which is slated to be released on November 19. The CEO of Rockstar parent company Take-Two, Strauss Zelnick, recently said marketing for GTA 6 kicks off this summer ahead of its now seemingly locked-in release date.

The price of GTA 6 continues to be one of the hottest topics in all of video games, with some expecting Rockstar to charge up to $100 for the game, although there’s no evidence either way right now. One thing Zelnick has been clear on, however, is denying rumors that GTA 6 will be a digital-only release upon its initial launch.

Recently, PlayStation gamers began fooling their friends by adding GTA 6 to their Recently Played list.

Vikki Blake is a reporter for IGN, as well as a critic, columnist, and consultant with 15+ years experience working with some of the world’s biggest gaming sites and publications. She’s also a Guardian, Spartan, Silent Hillian, Legend, and perpetually High Chaos. Find her at BlueSky.