Zdenek_Valter

That's apparently how I figured it out.
I removed the comments in the highlighted lines in bold (the text after the semicolon).
See above.
A functional startup script is like this:

; X5SA Start Code
G21; Set units to millimeters
G90; Set all axis to Absolute
M82
;
; Uncomment the line below to enable ABL Mesh probing
;G29 ; Probe bed mesh for ABL
; For best results do not run nozzle heater while performing ABL
M107 T0; Disable all fans
M140 S{material_bed_temperature_layer_0}
M104 S{material_print_temperature_layer_0} T0
M190 S{material_bed_temperature_layer_0}
M109 S{material_print_temperature_layer_0} T0
G28; Home all axis
G1 Z15.0 F6000; Raise nozzle to prevent scratching of heat bed
G1 X0 Y0 ; Move nozzle to Home before heating
G0 E3 F200
G92 E0 ; Set Extruder position to zero
; Uncomment the following lines to enable nozzle purge line along left edge of bed
;G1 Z2.0 F3000 ; Raise Z axis
;G1 X1.1 Y20 Z0.2 F3600.0 ; Move to purge line start position
;G1 Y220 F1500.0 E10 ; Draw first purge line
;G1 X1.4 F3600.0 ; Move to the side
;G1 Y20 F1500.0 E20 ; Draw second purge line
;G92 E0 ; Reset Extruder
;G1 Z2.0 F3000 ; Move Z Axis up a little to prevent scratching of Heat Bed
;G1 X5 Y20 Z0.2 F3600.0 ; Move over to finish nozzle wipe
;G92 E0