GitHub announced external custom properties in public preview on September 29, 2026. An organization can bring information such as repository ownership, service tier, or lifecycle stage from an existing system. A configuration management database, or CMDB, is an inventory of IT assets and their relationships. A company using one as its source of truth can synchronize selected fields into GitHub. Source
Who edits the values
Ordinary custom properties can be managed inside GitHub. With the external version, the connected system owns and updates the values, and users see them as read-only in the GitHub interface. The integration keeps its fields in a dedicated namespace. That helps administrators distinguish externally managed metadata from properties edited directly in GitHub. Source
Using the metadata
GitHub says the synchronized fields work in repository views, filters, and ruleset targeting. A team might filter repositories by service tier before applying a governance rule. Port.io is the first integration partner named in the announcement, and organizations may also build their own connections with the external properties APIs. The feature is currently a public preview. Source