It is closest to marlin. I use a modified marlin post processor in estlcam for gcode generation. Klipper doesn’t like the leading zero in gcode commands like G01 vs G1. You can deal with this in a postprocess like estlecam by defining that pretty easy. Others have made a macro for G01 to call G1 and pass the arguements. I do have a couple simple macros and a couple settings Ive posted about here.