Enhancements

Improved nested-object policy type, needed for Containers policy
Added support for sorting enum fields by their localized labels, used in new Containers policy

Enterprise Policies

Added support for Containers policy to set the initial set of tab containers
Added support for AllowFileSelectionDialogs policy to disable file selection dialogs
Added support for DisableEncryptedClientHello policy to disable use of the TLS feature Encrypted Client Hello (ECH)
Added Fallback option to DNSOverHTTPS policy to determines whether Firefox will use your default DNS resolver if there is a problem with the secure DNS provider
Added support for HttpAllowlist policy to configure sites that will not automatically be upgraded to HTTPS
Added support for HttpsOnlyMode policy to configure the HTTPS-Only mode
Added support for PostQuantumKeyAgreementEnabled policy to enable or disable post-quantum key agreement for TLS
Added support for TranslateEnabled policy to enable or disable the local translation feature
Added support for PrivateBrowsingModeAvailability policy to set the availability of private windows. It cannot be used together with the DisablePrivateBrowsing policy
Added FirefoxLabs option to UserMessaging policy to enable or disable the “Firefox Labs” section in the Firefox settings
Added support for MicrosoftEntraSSO policy to allow single sign-on for Microsoft Entra accounts
Added support for identity.fxaccounts.toolbar. and security.block_fileuri_script_with_wrong_mime in Preferences policy
Added private_browsing option to ExtensionSettings policy to configure whether an extension should be enabled in private browsing
The SearchEngines policy is no longer ESR only
Removed WhatsNew option from UserMessaging policy (Thanks, berkaynayman!) and removed it from existing configurations
Added support for additional cryptographic ciphers to DisabledCiphers policy

Translations

Fixed wrong environment variable in description of Certificates|Install policy
Updated wording for AutofillAddressEnabled and AutofillCreditCardEnabled policies
Updated Russian translation (Thanks, solokot!)