Google has released an Chrome Extension "Ad Transparency Spotlight" (Alpha) which is devised to show users more visibility into data used to personalise ads. It's also give users more control over that data.

At the time of this alpha release (July 2020), it only shows information about those ads purchased through Google Ads that have implemented the Ad Disclosure Schema (https://github.com/Ads-Transparency-Spotlight/documentation/blob/main/implement.md).

Google hopes that others will adopt the Ad Disclosure Schema.

[chrome.google.com...]