Google Docs „cello.db“

I‘m working on a case where Google reported videofiles containing csa-content to NCMEC.

During investigation of the seized device I found the filenames of the reported videofiles in „cello.db“ located at:

data\data\com.google.android.apps.docs\app_cello\<ACCOUNT_NAME>\cello.db

This database refers to Google Docs. As I know, Google Docs displays only documents (except media embedded in documents). The question is now: How or why does a videofile generate an entry in the cello.db? If the media was embedded in a document I would expect to find only the document in cello.db?

Navigating on the cloud to a folder containing only media files with Google Docs results in an empty folder.

Anybody an idea?

Thanks!