… value

Create a GCode generator field for each machine.
Default is for grbl.
In cam-gcode-raster and cam-gcode-laser-cut, each gcode writing will pass inside the generator and will return the appropriate GCode.

No modification in gCode writing with default generator but with the generator "marlin" this will change the way the laser will turn on and movements to be compatible with stock marlin on 3D printer or so.
For tool on/off the "gCodeToolOn" will be insert at each Intensity change and you can use $INTENSITY variable inside gCodeToolOn to get back the intensity.
By exemple, the GRBL gcode :

G0 X10.0 S100

Will become on Marlin, with gCodeToolOn set to "M106 $INTENSITY" :

M106 S100
G0 X10.0

In Raster mode, GRBL gcode
G1 X10.0 Y20.0 S100
X11.0 Y20.0 S30

will become in marlin :
M106 S100
G1 X10.0 Y20.0
M106 S30
G1 X11.0 Y20.0