The Log Keeper plugin tracks and records the last modification time of notes by updating a timestamp in the YAML frontmatter whenever content changes. The timestamps follow the ISO 8601 format and get updated automatically as you type, ensuring precise and consistent metadata for each note. This metadata can be used with plugins like Dataview and Contribution Graph to visualise your editing habits over time, much like a GitHub contribution calendar. The plugin is designed to work silently in the background.