library_construction_protocol: For single cell capture and sequencing library construction the protocol described in the 10x Genomics User Guide 'Chromium Next GEM Single Cell 3' Reagents Kits v3.1 (Dual Index)' (CG000316 RevD) was followed. GEM generation and barcoding was performed using a 10x Genomics Chromium or Chromium X device. Gene expression libraries were constructed as recommended by 10x Genomics. The CRISPR screening library construction was performed as described in the user guide, whereby 11 cycles with 5 µL input were performed for the feature PCR, and 9 cycles with 10 µL input were applied for the sample index PCR. To enhance Cas12a capture, a customized Cas12a screening library protocol was applied as described in the associated manuscript.