Random X Purge Line

I made this using settings for my MK4S. I don't know if it will work for anything else. YMMV.

Copy and Paste this code to your start G-Code in the Printers tab of PrusaSlicer.  Make sure to copy and paste a backup of your original code into Notepad just in case.

{local rnd_x = random(20, 80)*0.1}

{local purge_x = random(0, (print_bed_max[0] - 51) 10) 0.1}

M17 ; enable steppers

M862.1 P[nozzle_diameter] A{(filament_abrasive[0] ? 1 : 0)} F{(nozzle_high_flow[0] ? 1 : 0)} ; nozzle check

M862.3 P "[printer_model]" ; printer model check

M862.5 P2 ; g-code level check

M862.6 P"Input shaper" ; FW feature check

M115 U6.1.3+7898

M555 X{(min(print_bed_max[0], first_layer_print_min[0] + 32) - 32)} Y{(max(0, first_layer_print_min[1]) - 4)} W{((min(print_bed_max[0], max(first_layer_print_min[0] + 32, first_layer_print_max[0])))) - ((min(print_bed_max[0], first_layer_print_min[0] + 32) - 32))} H{((first_layer_print_max[1])) - ((max(0, first_layer_print_min[1]) - 4))}

G90 ; use absolute coordinates

M83 ; extruder relative mode

M140 S[first_layer_bed_temperature] ; set bed temp

M104 T0 S{((filament_notes[0]=~/.*HT_MBL10.*/) ? (first_layer_temperature[0] - 10) : (filament_type[0] == "PC" or filament_type[0] == "PA") ? (first_layer_temperature[0] - 25) : (filament_type[0] == "FLEX") ? 210 : (filament_type[0]=~/.*PET.*/) ? 175 : 170)} ; set extruder temp for bed leveling

M109 T0 R{((filament_notes[0]=~/.*HT_MBL10.*/) ? (first_layer_temperature[0] - 10) : (filament_type[0] == "PC" or filament_type[0] == "PA") ? (first_layer_temperature[0] - 25) : (filament_type[0] == "FLEX") ? 210 : (filament_type[0]=~/.*PET.*/) ? 175 : 170)} ; wait for temp

M84 E ; turn off E motor

G28 ; home all without mesh bed level

G1 X{rnd_x} Y-4 Z5 F4800; (Original G1 X42 Y-4 Z5 F4800)

M302 S160 ; lower cold extrusion limit to 160C

{if filament_type[initial_tool]=="FLEX"}

G1 E-4 F2400 ; retraction

{else}

G1 E-2 F2400 ; retraction

{endif}

M84 E ; turn off E motor

G29 P9 X10 Y-4 W32 H4

{if first_layer_bed_temperature[initial_tool]<=60}M106 S100{endif}

G0 Z40 F10000

M190 S[first_layer_bed_temperature] ; wait for bed temp

M107

;

; MBL

;

M84 E ; turn off E motor

G29 P1 ; invalidate mbl & probe print area

G29 P1 X0 Y0 W50 H20 C ; probe near purge place

G29 P3.2 ; interpolate mbl probes

G29 P3.13 ; extrapolate mbl outside probe area

G29 A ; activate mbl

; prepare for purge

M104 S{first_layer_temperature[0]}

G0 X{purge_x} Y-4 Z15 F4800 ; move away and ready for the purge

M109 S{first_layer_temperature[0]}

G92 E0

M569 S0 E ; set spreadcycle mode for extruder

;

; Extrude purge line

;

G92 E0 ; reset extruder position

G1 E{(filament_type[0] == "FLEX" ? 4 : 2)} F2400 ; deretraction after the initial one before nozzle cleaning

G0 E7 X{purge_x + 15} Z0.2 F500 ; purge

G0 X{purge_x + 25} E4 F500 ; purge

G0 X{purge_x + 35} E4 F650 ; purge

G0 X{purge_x + 45} E4 F800 ; purge

G0 X{purge_x + 48} Z0.05 F8000 ; wipe, move close to the bed

G0 X{purge_x + 51} Z0.2 F8000 ; wipe, move quickly away from the bed

G92 E0

M221 S100 ; set flow to 100%