OpenDBT is a Python library and CLI tool that extends dbt-core functionality through runtime patching. It provides enhanced capabilities including custom adapter integration, local Python model execution, DLT job integration, Airflow orchestration, multi-project (DBT Mesh) support, and an advanced documentation UI with column-level lineage. The architecture uses runtime patching to modify dbt's behavior without changing its source code, featuring a modular design with version-specific adaptations for dbt v1.7 and v1.8+, shared components for cross-version functionality, and dedicated integrations for Airflow and catalog generation. Entry points include the 'opendbt' CLI command, OpenDbtProject Python API, and Airflow operators. Data flows involve user CLI commands triggering enhanced dbt executions, documentation generation creating catalogl.json with lineage data, and Airflow operators orchestrating dbt tasks within DAGs.