The desktop app now stores each day as a real Markdown file in a folder you choose, readable in Obsidian or any editor. On first launch it asks you to pick a vault folder; from then on every entry is a YYYY-MM-DD.md file with frontmatter, and settings live alongside them. Your data is plain text you fully own.
The web version is unchanged and keeps IndexedDB. The same code picks its storage backend at runtime.
Download Compendium_0.6.0_aarch64.dmg below (Apple Silicon). Unsigned, so on first launch right-click the app and choose Open.