The unauthorised attack of 3190 in which Ruon Tarka and Cleveland Booker destroyed the device controlling the Dark Matter Anomaly with an illegal isolytic weapon, without stopping its makers.
The destruction of the DMA controller is the outcome of a story spread over several fourth-season Discovery episodes. In ...But to Connect, the worlds assembled by President Rillak vote to attempt peaceful contact with the unknown Species 10-C. Booker, whose homeworld Kwejian was destroyed by the anomaly, and the scientist Tarka reject the vote and leave with a prototype spore drive.
In All In they obtain the rare isolynium they need at a gambling den, and in Rubicon the USS Discovery tracks them down with Commander Nhan aboard as an observer. Burnham works out that the anomaly is a mining tool that will stay in one place for about a week, and Booker agrees to wait.
Tarka fires the weapon regardless, and the controller is destroyed. The power source he wanted turns out to be on the far side of the wormhole, and the 10-C put a new anomaly in place almost immediately.