The Diagrams.Net plugin integrates the diagrams.net online editor into Obsidian, allowing users to create and edit diagrams directly within their notes. This plugin provides full access to the diagrams.net feature set and shape libraries but requires an internet connection. Diagrams are saved as separate files alongside their image representations, enabling easy access and editing in any diagrams.net-compatible editor. The plugin supports moving and renaming diagrams within Obsidian while ensuring both associated files are updated. However, users should manually duplicate files if copying diagrams, as automatic association is not supported.