ATMega32U4 with a male USB plug.
Extra parts - post pcba:
- EC05E1220203 - 2.7mm low profile encoder (incompatible) | mouser | SnapEDA | datasheet
- EVQ-VVD00203B - 2.2mm low profile encoder (incompatible) | mouser | datasheet
- 292V1X24A - 3.8mm ring encoder (incompatible) | mouser | datasheet
- EC12E1220301 - 4.5mm encoder | mouser | datasheet
Note: The Molex USB C connector reaches a bit past the solder masks, but shouldn't affect the assembly process. (Fig. 1)