The purple boards slotted into the pairs of SIL headers are Pololu Stepper motor drivers ... This is a dual-layer board which may not be ideal for your own fabrication process.
[Neumi] over on Hackaday.IO wanted a simple-to-use way to drive stepper ... on-board AMS AS5600 magnetic rotary encoder (which senses the rotating magnetic field on the rear side of the motor ...