This appeared in Marlin via Prusa as M915 before becoming an option for G34. The better known G34 that uses a probe is equivalent to Z_TILT_ADJUST in Klipper.

I made a very slow video showing the marlin version in operation on my Ender 3 on my SKR mini board.

I implemented MECHANICAL_GANTRY_ALIGN as a Klipper macro almost immediately after getting klipper running on my SKR mini.

I still use this on my Prusa style printer, despite it having a driver for both setups. If i disturb the adjustable bed, I use this to set the gantry parallel to the top of the frame as a reference before running SCREWS_TILT_CALCULATE (G35 in marlin, use it) to set the plane through the 4 corners of the bed to be parallel to the Y axis and the level taken from the frame top. However in my START_PRINT routine i use Z_TILT_ADJUST because the bed doesn’t go out of tram once set up unless something really bad happens.

This requires TMC drivers to be set up (using UART or SPI) to allow software control of the stepper current. Without that, or if you use too high a current it may break your printer. This does not use STALLGUARD or sensorless homing.