The Chrome User Experience Report (also known as the Chrome UX Report, or CrUX for short) is a dataset that reflects how real-world Chrome users experience popular destinations on the web.
CrUX is the official dataset of the Web Vitals program. All user-centric Core Web Vitals metrics are represented.
CrUX data is collected from real browsers around the world, based on certain browser options which determine user eligibility. A set of dimensions and metrics are collected which allow site owners to determine how users experience their sites.
The data collected by CrUX is available publicly through a number of Google tools and third-party tools and is used by Google Search to inform the page experience ranking factor.
Not all origins or pages are represented in the dataset. There are separate eligibility criteria for origins and pages, primarily that they must be publicly discoverable and there must be a large enough number of visitors in order to create a statistically significant dataset.