So I closed the former "Intents to package" at Debian by e.g. sending an email to "971525-done@bugs.debian.org" with the following content:
Subject: Re: ITP: python3-briar-wrapper -- Wrapper around the Briar Headless REST API
Currently there's a lot of activity happening at Briar which results in this ITP getting closed.
Instead of building a desktop client with Python and GTK, we decided to go with a pure Java/Kotlin version using the Compose UI framework [0]. This has the advantage that we no longer need to build a separate REST API for the GTK client to consume but instead can use all the Java classes and methods directly. This saves us a lot of overhead and allows us to build a more feature-complete client throughout the next months, funded by the Prototype Fund [1].
Once the new desktop client is more mature, I will open a new ITP at Debian for a potential briar-desktop package. This package is currently blocked by Kotlin [2], just like the ITP of briar-headless was [3]. See this issue [4] in the meantime if you want to track Briar Desktop's inclusion into Debian.
I'd still find it super nice if one could type apt install briar-desktop one day.
We had this discussion before where I think one conclusion was that we need to get all our dependencies and Kotlin into Debian in a compatible version, which I fear probably will never happen.
I have this hunch however that it should be possible to package an uber-jar for debian which basically contains our own code plus all third party dependencies, including Kotlin in a single jar. That package would depend only on the JRE I think.
Doing some research using apt rdepends default-jre there are quite a number of packages to find and I bet there are many apps that do exactly that. One that I identified already is josm. It's a quite complex Swing application and available in Debian bookworm and Ubuntu focal. I have quickly glanced through what they ship in the deb: a 15MB jar file that clearly is an uber jar containing a bunch of dependencies which I could easily verify are third-party dependencies as defined in their ivy.xml.
So bottom line, I believe shipping to Debian might not be as hard as we anticipated