You may
- use it for free, for personal and professional work
- read, change and fork the source code
- share your changes
License
Sagittarius Orbit is released under the Apache License 2.0 with the Commons Clause condition.
You may not
- sell Orbit, or a product or service whose value comes mainly from it
- charge for hosting, support or consulting that is essentially Orbit itself
PHP, the web servers, the databases and the other tools Orbit downloads come from their own publishers and keep their own licenses.
The full texts ship with the source code.