Exactly. It's simply hiding a block you mined from the network and building on top of it in an attempt to get rewards from subsequent blocks for yourself. Works more often over time the higher % of network hashrate you have of course. My main point was they never reached 51% but that is what Qubic claimed on their website and what the headlines are running with. But no one is verifying anything of course. I think they briefly had ~35% hashrate at their peak briefly but can't sustain that consistently. They hover around 21% on average if you keep your eye on my link in that post.