Download the release zip(on the right sidebar, do not click code..download as zip). Extract directly to your Ashita directory(the folder with ashita-cli.exe in it!). Everything should fall into place.
This is an Arduino core to support the exciting new AVR DA, DB, and DD-series microcontrollers from Microchip. These parts are the latest and highest spec 8-bit AVRs available, and take the AVR ...