Is DeSo open source?

Can you please clarify whether DeSo, the decentralized social network, is indeed an open-source platform? Open-source software typically allows for transparency, collaboration, and customization by the broader community. It's important to understand if DeSo adheres to this principle, as it could significantly impact its long-term development, adoption, and potential for innovation. Is there a publicly available codebase that developers can contribute to or build upon?