Google Ads is introducing a new beta feature within conversion action details that allows advertisers to connect external data sources directly to their Google tag.
This new section labeled Get deeper insights about your customers’ behavior to improve measurement invites users to connect products like BigQuery or MySQL to enhance conversion metrics, campaign performance, and measurement signals.

This aligns with Google’s broader push toward first party data and improved signal quality, and the rollout appears gradual as the feature is currently marked as Beta.
This update was discovered by Hana Kobzová.