The files with .bst extensions are continuous files fully copied into the Brainstorm database. This is an internal file format that does not have any other purpose. Its purpose is not to be manipulated directly from a script.
For example, this is what you get in the database when applying a filter to a continuous file:
https://neuroimage.usc.edu/brainstorm/Tutorials/ArtifactsFilter#Apply_a_notch_filter
Or when using the menu "File > Export protocol > Copy raw files to database"