The motor power lines have some interesting (read: completely mismatched) color coordination going on—fixers take note.

They could also do with some more support and insulation (hot glue) on the solder joints.

Here's what we found on a quick tour of the main board:

GigaDevice GD32F103 ARM Cortex-M3

Six half-H bridge motor drivers, made up of two large MOSFETs each

Changjiang Electronics Technology Co., LTD CJ78M05 0.5A/5V voltage regulator

Two pairs of 0.007 ohm resistors by the power inlet (R007).

Resistors like these, with very low resistance, are used to sense current—helping to shut things down if a motor stalls out.