Origin trials can now be enabled by embedded scripts, based on tokens matching their third-party origin. Previously, it was possible for scripts to enable origin trials, but only when the token matches the origin of the containing document.
Allow third-party providers to experiment more effectively via origin trials. As in the origin trials explainer (see doc links), the goal is to encourage broad participation and feedback from web developers, while preventing burn-in of features or hampering iteration. Origin trials currently require opt-in/attribution for first-party origins, which causes undue friction for third-party providers. For some features, third-party providers are often in the best position to experiment and provide feedback.
Docs: https://github.com/GoogleChrome/OriginTrials/blob/gh-pages/explainer.md https://docs.google.com/document/d/1xALH9W7rWmX0FpjudhDeS2TNTEOXuPn4Tlc9VmuPdHA/edit https://web.dev/third-party-origin-trials
Explainers: Origin trials are a Chrome-specific experimentation framework, not a web platform feature.