Mind elaborating?
With third party cookie policies getting more stringent, many websites now use either a reverse proxy within the first party domain that points to third party servers, or they use a first party subdomain that points to third party servers.
In either case, it allows the servers belonging to the data gatherer to appear as first party, thus getting around third party cookie restrictions.
Combine that with browser fingerprinting, and you now have a harder but very viable way to replace the functionality third party cookies previously had.
This is completely transparent from the outside.
When I hear PMs say "this change will be completely transparent to clients" what they mean is, the client will see no difference, which means really, the details are hidden in a black - opaque - box.
Importantly however; Tech people can claim they are being 'transparent'. To them this can mean no visible difference to the user- and to everyone else means visible/public and available for scrutiny.
So yes, I am sure Zuckerberg is focused on 'transparency'.
But, I'ma guess probably not.
Doesn't transparent mean that the interface stays the same and clients can interact with the system in the same way as before without the need to change their code?
But don't despair - all isn't lost! You can fix it with sandpaper, after that you'll be able to see the glass and it will become transparent.
Please don't sue me if you don't like the result, however.