What are MonoDevelop's .pidb files?

Question

MonoDevelop creates those for every project. Should I include them in source control?

Answer 1

They're just cached code completion data. As the post Jon linked explains, the main reason is to save memory, though they do also save you from waiting for MD to parse all the source files and referenced assemblies when you open a project.

The pidb files can be regenerated pretty quickly, so there's no advantage to keeping them in the VCS. Indeed, as well as the VCS repository overhead, it could also cause problem if people are using different versions of MD with different pidb formats, so I'd strongly recommend against keeping them in source control.