While not linked to one single origin, this type of phrasing is common on Polish imageboards (like Wykop or regional 4chan clones). It is often deployed when a user sees a meme, a video of a chaotic situation—like the viral Bóbr Kurwa beaver encounters—or a political scandal that seems too absurd to be true.

Bober Kurwa - Exploring the Polish Culture with Bober Memes - TikTok

The phrase is a piece of Polish internet slang typically used as a reaction to something ridiculous, excessive, or high-intensity. It combines a misspelled dialect version of "more" ( wincyj ) with the ubiquitous Polish swear word kurwa and a file extension ( .rar ), implying a compressed archive of even more chaotic or extreme content. Breakdown of the Phrase