Rust version of OpenStratos, still in development. You will neeed Rust to compile/execute the software. You can install it (also for Raspberry Pi) in rustup.rs.
This software is licensed under the GNU General Public License version 3. You can use, copy, modify the software as long as all the derivative work is published under the same license. A copy of the license can be found in the LICENSE.md file of the repository where a detailed explanation of the copying rights can be found.