An accessibility center of excellence acts as a central hub of expertise within a larger organization, setting internal accessibility standards and guidelines, providing training, reviewing high-risk projects, and supporting the network of accessibility champions embedded in individual product teams, rather than trying to review every single feature itself.
This model is most common in larger organizations with many products or a large digital footprint, where a single central team could not realistically handle every accessibility review directly and instead focuses on building capability and consistent standards across the wider organization.