I've recently been trying to save space on my machine and started using TreeSize to analyse folder structures / sizes
This led me to the discovery that a lot of my Visual Studio projects have SDF files inside them. In one case, an app folder is 80Mb, 50Mb of which is this SDF file. This app doesn't use SQL Server Compact (although it has a SQLite database). The SDF file doesn't appear in the project files in Visual Studio.
Where do these files come from, and are they safe to remove?