What’s the Meaning of Burning Time? What’s the Difference Between mS and mm/sec, mm/min?

What is feed rate?

meaning of mm/sec and mm/min, please see here, You can simply think of it as cutting speed.

What is burning time?

The burning time is an original creation of neje. The image carving of neje is not controlled by G code, but by accurately controlling the time when the laser stops at each pixel to control the carving level. The time for each pixel is burning time.