I don’t remember when or why exactly I switched, it might have been an issue with the java version, some skin applying incorrectly, outdated ubuntu version and subsequently unavailable updates in the apt repository, or some combination of those.
I could try through apt again, since I’m now using debian, yes.
I tried again, on Debian GNU/Linux 12 (bookworm) using the josm-installer package:
josm-installer/oldstable,oldstable,now 0.0.2+svn18515 all [installed]
Editor for OpenStreetMap (installer)
At first I ran into the same problem as JOSM auf MANJARO since I did not have the package openjfx installed and the starter script at /usr/bin/josm requires it. Just running java -jar /usr/share/josm/josm.jar does work too, it complains about some missing parameters, oh well.
The startup script could check if openjfx is installed or not;
if ! dpkg -l openjfx 2>&1 | grep -q "ii"; then
echo "Error: openjfx is not installed. Please install it using 'sudo apt install openjfx'."
fi
that may be distribution dependant though, I don’t know.