In the past I'd recommended Trilium Notes as a good FLOSS alternative to Obsidian for a note taking database app, but unfortunately today after failing to restore a trilium backup file to a new install, and finding that the documentation on backups isn't accurate (as in, there are not buttons in the app that the documentation claims are there, and nothing I have tried has worked to restore the backup), I discovered on the github a Claude.md in the repository, and the commit history shows that in the past few months Claude has become one of the most prolific contributors on the project.
If anyone is using this app based on my previous recommendation, I'd personally suggest migrating to a different note-taking app that isn't vibe-coded (and exports backups to plain text, instead of some database format), perhaps CherryTree?
SQLite is the single most widely deployed piece of software on Earth. You don't need to know everything about every database format, or even how to open a SQLite file for viewing (many FOSS apps that can do this), but you should at least know what it is.
I mean, I'm sure there's a very common stitch pattern used in most people's clothing, but I'm guessing most people wouldn't be familiar with it. 🤷
I've never had cause to work with anything related to databases. I'm familiar with SQlite being a database software, but I haven't ever had to open a .db file before, so I wouldn't have known .db is specifically the SQLite format.