flexi-bot/docs/marlin/_gcode/M218.md

tag	title	brief	author	requires	group	codes	notes	parameters	examples
m0218	Set Hotend Offset	Set the offset of a hotend (from hotend 0).	thinkyhead	EXTRUDERS>1	calibration	M218	- Requires 2 or more nozzles. - The default hotend offsets are set with `HOTEND_OFFSET_[XYZ]`. - Z hotend offset only available with `DUAL_X_CARRIAGE` or `SWITCHING_NOZZLE`. - View current hotend offsets with [`M503`](/docs/gcode/M503.html). - If `EEPROM_SETTINGS` is enabled, these offsets are saved with [`M500`](/docs/gcode/M500.html), loaded with [`M501`](/docs/gcode/M501.html), and reset with [`M502`](/docs/gcode/M502.html).	tag optional description values T true Hotend index. Active extruder by default. tag type index int tag optional description values X true Hotend X offset tag type offset float tag optional description values Y true Hotend Y offset tag type offset float tag optional description values Z true Hotend Z offset. Requires `DUAL_X_CARRIAGE` or `SWITCHING_NOZZLE`. tag type offset float

To keep nozzles aligned to the work area between tool-changes, the firmware needs to know how they relate to each other.