PostgreSQL is a powerful, open source object-relational database system with over 35 years of active development. It is released under the PostgreSQL License, a liberal Open Source license similar to the BSD or MIT licenses.

Key features of PostgreSQL:

• Robust ACID compliance and transaction support
• Advanced query planner and optimizer
• Rich set of built-in and user-defined data types
• Extensive security features including native SSL support

Kubernetes Compatibility:

• Official Docker images are maintained by the PostgreSQL Community
• Available on Docker Hub as 'postgres'
• Well-documented Kubernetes deployment patterns
• Supports cloud-native features like streaming replication

The software is maintained by the PostgreSQL Global Development Group, a diverse group of companies and individual contributors. The official Docker images are maintained by the PostgreSQL Community and regularly updated with security patches and new releases.