X released source code for the system that recommends organic posts and advertising in its For You feed. The company says the new version relies on a Grok-based model that studies sequences of clicks, likes, replies, reposts, and other engagement. It gathers posts from followed accounts and unfamiliar ones, removes blocked or restricted material, then ranks what remains according to predicted interest. Elon Musk also promised updates to the public code every four weeks. An earlier release in 2023 was criticized as incomplete transparency, and the new disclosure arrived while X faced regulatory pressure in Europe.

Published code allows specialists to inspect part of the sorting machinery. It cannot reveal the business decision that defines a successful feed, the data used to train the model, the live adjustments made during an election or crisis, or the difference between the repository and the system running on a phone. A recommendation engine learns from behavior that it has already helped produce. The post placed first receives attention, that attention becomes engagement, and engagement returns as evidence that similar posts deserve promotion. Opening the code gives the public a diagram of this loop. Accountability requires access to its goals, changes, and effects as well. A user can now read thousands of lines on GitHub and still have no practical explanation for the next post selected for the top of the screen.