MPR - makedeb Package Repository (previously know as the DUR - Debian User Repository) is a source for PKGBUILDs that can be transformed into .debs using the tool mentioned in its name, makedeb. It also has a wrapper for it called tap (the successor to mpm), which is the equivalent to what AUR helpers are for Arch-based distros.

Its objective is to help diminish the need for installing PPAs or using other package formats, like snaps or flatpaks in order to get upstreamed projects and more up to date packages on Debian and Ubuntu based distros. As a relatively new project it only has a handful of packages, more precisely 60 of them at the time of writing. But I do believe this is one huge feature for Debian-based distros, if it can grow a large enough package count and community.

As someone who doesn't understand a lot of what's needed for contributing the least I can do is to spread the word and call for people that are willing to help the project grow. So help them out if you can, their Matrix space is always open and can be really helpful!