That is just outright depressing 
!
As far as I can see from a quick look, NeuroDebian now managed to break almost all psychtoolbox packages for almost all supported distributions in one way or the other atm., apparently without the maintainers noticing the brokeness. Unfortunately the level of care and quality has been somewhat degrading already since 2 years, but really went on a crash dive in the last six months.
I think there might be more brokeness than what you found:
The matlab-psychtoolbox-3[-nonfree] packages are of version 3.0.22.3, and need matching psychtoolbox3-[common/libs] packages, but while the 3.0.22.3 Matlab packages are shipped for all supported Debian/Ubuntu distributions (even ones that are completely unsupported by 3.0.22, like Ubuntu 20.04-LTS !), the matching psychtoolbox-3-common packages are still stuck at 3.0.22.2 instead of 3.0.22.3! I’d expect this means that any upgrade to 3.0.22.3 on older Ubuntu/Debian will fail, and initial installation is impossible, due to dependency version mismatches.
The octave-psychtoolbox-3-nonfree packages is 3.0.22.3, but shares all the problems of broken dependencies on all distros apart from Ubuntu 26.04/Debian 13 as the Matlab packages.
octave-psychtoolbox-3 itself seems to be stuck on v3.0.22.2 instead of 3.0.22.3 for absolutely no reason on all distros older than Ubuntu 26.04. Strong work!!
In other words, the only up to date package in proper working order is probably Psychtoolbox 3.0.22.3 for Octave on Debian 13 and Ubuntu 26.04-LTS.
The agreement with NeuroDebian was that they wouldn’t have an issue with our new license model, or with adding the license management libraries, so far so good. But so far at least 3 attempts to actually get it implemented failed, not because it would be difficult, but because NeuroDebian dropped the ball one way or the other. Given that they did an amazingly good job with Psychtoolbox for 14 years, since adding PTB in 2011, and I know they are highly competent, I can only imagine that the one person team is totally overworked and short on time, and that causes them to cut corners and make much more mistakes.
NeuroDebian to my knowledge is still completely volunteer work, and pretty much a one man show, not meaningfully funded in any way.
So I don’t know what the future will be here, or if there will be one, given the current state of things.
Right now, one way for you to keep going with the NeuroDebian versions for Debian 13 Trixie (or Ubuntu 26.04-LTS) would be to manually extract the libLexActivator.so from our zip file and copy it into the
/usr/share/psychtoolbox-3/PsychBasic/PsychPlugins/ folder, and then run the usual SetupPsychtoolbox() procedure. That might make it work iirc.
For most people, using our zip file might be much less painful and more straightforward right now. The only people that must use ND atm. are the ones that want to use Psychtoolbox 3.0.22 for Octave on Ubuntu 26.04-LTS and maybe Debian 13, as we currently don’t ship compatible mex files for the Octave 10 or later versions that are part of these recent distributions.
-mario