MESSAGE_DISALLOWED, MESSAGE_PERMITTED, MESSAGE_FORCED constants are currently used on db/message.php while declaring message providers.

Example:

$messageproviders = [

    'contactdataprotectionofficer' => [

        'defaults' => [

            'popup' => MESSAGE_PERMITTED + MESSAGE_DEFAULT_ENABLED,

            'email' => MESSAGE_PERMITTED + MESSAGE_DEFAULT_ENABLED,

        ],

        'capability'  => 'tool/dataprivacy:managedatarequests'

    ]

 ....

Previous to this issue, the definition was:
MESSAGE_PERMITTED + MESSAGE_DEFAULT_LOGGEDIN + MESSAGE_DEFAULT_LOGGEDOFF

This is a bitwise combination to reach all possibilities:
ENABLED: Will enable the provider by default.
PERMITTED: will let the user decide to enable or disable
DISALLOWED: Will block the use from changing the setting and disable it.
FORCED: Will block the use from changing the setting and enable it.

This does not make sense anymore, since having only one "enabled" setting DISALLOWED implies not ENABLED and FORCED implies ENABLED, while permitted is already implicit if not DISALLOWED or not FORCED...

IMO only two options are needed right now.

ENABLED (not using it will mean disabled).
FORCED (will mix with ENABLED or not... and not using it will mean permitted).

The problem here is to make something backward compatible. Probably creating something apart with a new system.