This is a 2.6 mm offset for the Anycubic M3 flexible build plate system made by Wam Bam.
The system can be found here: https://whambam3d.com/products/172-x-110-anycubic-photon-m3
Remember to loosen the four screws around the build plate before re-zeroing and follow Anycubic's instructions.
3D PRINTING SETTINGS
I printed it in Petg so it doesn't react with the resin fumes.
The author hasn't provided the model origin yet.