Is mina open source?

Could you please clarify whether Mina is an open-source project? I'm interested in understanding the transparency and collaboration aspects of its development. Is its codebase freely accessible to the public? Are developers encouraged to contribute and participate in its evolution? Additionally, does Mina adhere to open-source principles, such as sharing source code, enabling community involvement, and fostering innovation through collaborative efforts? Thank you for your assistance in clarifying this matter.