Welcome to the Klipper project!
This project implements a 3d-printer firmware. There are two parts to this firmware - code that runs on a micro-controller and code that runs on a host machine. The host software does the work to build a schedule of events, while the micro-controller software does the work to execute the provided schedule at the specified times.
There is also developer documentation available.
Klipper is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Klipper is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Klipper. If not, see http://www.gnu.org/licenses/.