Personally I’m not very interested in Debian, because its fundamental release cycle doesn’t provide what I as a developer need most: up-to-date software libraries needed for building Plasma and other KDE software from git master.
Hi @ngraham
I’m assuming that you’re referring to Debian Stable version. I agree that Stable is very old. Dusty-fossilized-old. In turn, not attractive to most developers. Whom enjoy recent versions.
My original post above is about the other and more recent versions of Debian. For those not familiar with those. They are called Testing, Unstable, and Experimental. I was not referring to the dusty old Debian Stable version. Maybe my original post was not clear about this.
For those not familiar with the Debian Testing version automated installer, it presently includes KDE Plasma version 6.2.5-1. Which was released December 31st, 2024. In other words, just 4 weeks before my original post. And roughly 6 weeks from now. Debian Experimental version includes a more recent version. Presently KDE 6.2.91.1-1. Which was released less than 2 weeks ago.
There are multiple ways to get more recent package versions on Debian. Including very fresh-out-of-the-oven-version 
Below is the same reply as above. But with details for those interested.
Newer version for developers
Below are two suggested resolutions to consider for developer interested to contribute to more recent versions of both KDE Plasma 6 on Debian 13 Trixie.
Resolution 1: Testing or Experimental versions
Debian 13 Trixie Experimental automated installer presently includes KDE Plasma version 6.2.91.1-1. Which was released less than 2 weeks ago.
Debian 13 Trixie Testing automated installer presently includes KDE Plasma version 6.2.5-1. Which was released December 31st, 2024. In other words, just 6 weeks ago.
For those not familiar with Debian and Ubuntu release relationships. Ubuntu LTS releases are syncs/powered by Debian Testing. For Ubuntu non-LTS releases, Ubuntu syncs with Debian Unstable.
Resolution 2: Flatpak
To get cutting edge KDE 6 version for developer, how about creating a Flatpak installer on https://flathub.org ?
For interested contributors, those documentations might be of interest:
When configured appropriately, Flatpak has very strong security. For both developers and end-users interested in stronger security, this Flatpak configuration can easily be done, per app, or for all apps, with this amazing Flatseal app. Including on-off GUI switches.
Resolution 3: Any other?
Do you have any other resolution to suggest for developers to get newer version of KDE plasma on Debian 13 Trixie?
Newer version for end-users
In the future, after Debian 13 Trixie Testing turns into a Stable version. For end-users to get more recent version of KDE Plasma 6. Below are three suggested resolutions to consider.
Resolution 1: Backport
With Debian Stable, when adding this Backport repository, end-users could get ongoing updates for KDE Plasma 6.
For those not familiar with this Backport, this related doc might be of interest
Search presently available Backport packages. Those include recent Linux Kernel versions.
Plasma 6 is not yet added to Backport, obviously. Any volunteer interested to contribute this?
Resolution 2: Flatpak
Flatpak works really well on a Debian Stable. I used it for years now. How about creating a Flatpak for KDE Plasma 6 packages?
As you probably know, Flathub already has lots of successful System Flatpaks
Resolution 3: Any other?
Do you have any other resolution to suggest for end-users to get newer future versions of KDE plasma on Debian 13 Trixie?