Since my caliper didn't fit to the original holder, I changed it a bit. Now it fits shorter variants of 150mm calipers, but should fit slightly longer ones as well. I recommend measuring everything before printing.
Sources: https://cad.onshape.com/documents/7e3692641ce4d4147e1638cd/w/71f4b6d32dbadf8b16a8fb6f/e/e2622af885247a0d1de434f6?renderMode=0&uiState=662e2e0794cbae7476dc098f
The author remixed this model.
Changed to fit shorter calipers