Debian developers now have an official way to publish and test add-on package repositories, as the Debusine project has opened its repository feature in public beta.
The new service, available at debusine.debian.net, allows Debian Developers and Debian Maintainers to create APT-compatible repositories that function similarly to the well-known Ubuntu’s PPAs but are built specifically for the Debian ecosystem.
Debusine itself is a relatively new project within Debian’s infrastructure. It was introduced publicly at DebConf and has been developed to modernize and unify Debian’s internal workflows for package building, testing, and quality assurance. Until now, much of this work has taken place behind the scenes. With the launch of repositories in beta, Debusine is becoming directly usable for day-to-day development tasks.


Not really? From this page, all it looks like you need is a salsa.debian.org account. They call this being a “Debian developer”, but registration on Debian Salsa is open to anybody, and you can just sign up.
Once you have an account, you can use Debian’s Debusine normally. I don’t really see how this is any different from being required to create an Ubuntu/Launchpad account for a PPA. This is really just pedantic terminology, Debian considers anybody who contributes to their distro in any way to be a “Debian Developer”, whereas Ubuntu doesn’t.
If you don’t want to create an account, you can self host debusine — except it looks like you can’t self host the server that powers PPA’s. I consider this to be a win for Debusine.
According to the Debian Wiki, merely having a salsa account is not sufficient.
Edit, to address the last line in your comment:
The value of Ubuntu’s PPA service is it gives anyone a managed and hosted repository and a multi-architecture build farm, for free, so you don’t have to self-host. Self-hosting Debusine would not be comparable.
If a self-hosted Debian repository is all you want, that has been possible forever, using any of a variety of tools.
Debían developer is a specific position that you apply for. Anyone can be a maintainer. Well, I had to get approved but I don’t know the qualifications, I already had code in Debían vía GNOME.