i was trying to install an external .opm-package withe the Web UI
Apparently since 6.0.9 they have a new feature, to disable external package installation by default.
(From the 6.0.9 Changelog:
What’s New
Updated translations, thanks to all translators.
Added improvements to the support data collector plugins.
Enhanced package manager:
Not verified packages can’t be installed by default (via GUI + OTRS console).
Added sysconfig setting ‚Package::AllowNotVerifiedPackages‘ to allow installation of not verified packages (disabled by default).
Display a notification if setting ‚Package::AllowNotVerifiedPackages‘ is active.
)

When I try to change the setting on the Web UI nothing comes up.

And directly on the server, the only setting I cound find was the GET-method for checking in Kernel::Config wether the setting was enabled or disabled inside the Package.pm file.
See:

I don't know if the GET-method checks the Config.pm and if it's safe to just add the line Package::AllowNotVerifiedPackages = true
to make it happen. So i figured, I'd better ask for your input, since this OTRS is active in production and I don't wanna mess it up

Thanks in advance for your help!