Unity’s Built-in Render Pipeline is a general-purpose render pipeline.
The Built-in Render Pipeline is more limited in terms of custom extension than Scriptable Render Pipelines, but you can choose between different rendering pathsThe technique Unity uses to render graphics. Choosing a different path affects the performance of your game, and how lighting and shading are calculated. Some paths are more suited to different platforms and hardware than others. More info
See in Glossary and extend its functionality with command buffers and callbacks.