FirstPartySetsOverrides

This policy provides a way to override the list of sets the browser uses for First-Party Sets features. Each set in the browser's list of First-Party Sets must meet the requirements of a First-Party Set. A First-Party Set must contain a primary site and one or more member sites. A set can also contain a list of service sites that it owns, as well as a map from a site to all of its ccTLD variants. See https://github.com/WICG/first-party-sets for more information on First-Party Sets are used by Google Chrome. All sites in a First-Party Set must be a registrable domain served over HTTPS. Each site in a First-Party Set must also be unique, meaning a site cannot be listed more than once in a First-Party Set. When this policy is given an empty dictionary, the browser uses the public list of First-Party Sets. For all sites in a First-Party Set from the replacements list, if a site is also present on a First-Party Set in the browser's list, then that site will be removed from the browser's First-Party Set. After this, the policy's First-Party Set will be added to the browser's list of First-Party Sets. For all sites in a First-Party Set from the additions list, if a site is also present on a First-Party Set in the browser's list, then the browser's First-Party Set will be updated so that the new First-Party Set can be added to the browser's list. After the browser's list has been updated, the policy's First-Party Set will be added to the browser's list of First-Party Sets. The browser's list of First-Party Sets requires that for all sites in its list, no site is in more than one set. This is also required for both the replacements list and the additions list. Similarly, a site cannot be in both the replacements list and the additions list. Wildcards (*) are not supported as a policy value, nor within any First-Party Set in these lists. All sets provided by the policy must be valid First-Party Sets, if they aren't then an appropriate error will be outputted. On Microsoft® Windows®, this policy is only available on instances that are joined to a Microsoft® Active Directory® domain, joined to Microsoft® Azure® Active Directory® or enrolled in Chrome Browser Cloud Management. On macOS, this policy is only available on instances that are managed via MDM, joined to a domain via MCX or enrolled in Chrome Browser Cloud Management. This is the equivalent of the RelatedWebsiteSetsOverrides policy. Either policy may be used, but this one will be deprecated soon so the RelatedWebsiteSetsOverrides policy is preferred. They both have the same effect on the browser's behavior.