I have just updated the mir-kiosk snap, which includes the latest mir release, fixing various issues. We are also in the process of deprecating mir-libs snap and instead the mir-libs slot is part of the mir-kiosk snap. So you should uninstall the mir-libs snap.
I made some slight changes to your code here:
The main thing is to avoid having mir libraries in the final snap, so they are not loaded by accident instead of the libs provided through the mir-libs content i/f. This ensures compatibility as we update the mir-kiosk snap.
For now you’ll have to manually connect the mir-libs plug (at least until this is approved: Mir-kiosk:mir-libs Auto-Connection)
snap connect netconsole-reader:mir-libs mir-kiosk:mir-libs
After a reboot, your netconsole app starts up as expected with the changes from my branch.