As far as I know, that is a feature in grbl v1.1+. It's not in a program demo that I'm aware of. It is not needed when using our professional image to gcode software & streamer programs. A quality precision CNC laser diode engraving machine with a proper CNC controller is required with our software too.
If they only recommend or require you using grbl 1.1+ with there software, it's a tell tail sign they are struggling to catch up with the raster engraving quality that can be achieved when using our programs, even though they may have copied the processes we invented/developed.
I only recommend Larry's MultiMode grbl 1.0c hex that is available for download here on our forum's main page to use with our image to gcode software programs & gcode streamer for raster laser engraving grayscale or black & white photos/images.
Here is a compilation of raster laser engraved photos done by me. No
Dynamic Laser Power was ever needed or used with any of our photo/image laser engravings. https://discuss.inventables.com/t/laser ... gory/29990