The source code is on GitHub if you want to install and run it yourself. It is available under the MIT license, which is one of the most liberal in terms of allowing you to do what you want with the code without restriction.
It has similar capabilities to other 3D printing slicers like Cura, Simplify3D, and PrusaSlicer.
It is very different in several important ways:
There is no software to install or maintain. It's just a web page.
As a web app, it runs in a security sandbox and cannot access data on your hard drive
It offers several modes of operation for most of the common maker tools, like CNC mills
It is updated quite frequently (several times a week) with bug fixes and new features
Kiri comes from Kiri-e, which is the Japanese art of paper-cutting. Moto is short for "modeling tool".