The properties system allows you to filter and visualize nodes based on their properties, providing a powerful way to focus on specific aspects of your vault's structure. You can both filter the graph to show only notes with specific properties and visualize these properties directly on the graph using colored arcs around the nodes. If multiple properties are displayed, or if the tags are also used, each group will be displayed on its own circle level

The settings are the same as for the Tags feature, please see the details there.

The properties system is compatible with Dataview plugin properties, allowing you to also use inline properties and their values.