You will need [ch32v003fun](https://github.com/cnlohr/ch32v003fun/) in next to the folder for this repository.
The `gdbinit` file contains the device path for uploading via a Pi Pico with [PicoRVD](https://github.com/aappleby/PicoRVD). This is triggered with `make flash`.
If you have an official WCH programmer you can probably run `make cv_flash` to use minchlink from ch32v003fun, but I can't test this.