Comment 15 for bug 1865158

You used the old version for the debug information. Please update by reinstalling using the instructions in https://launchpad.net/linux-purge/+announcement/15313

I do not understand how you get kernel updates as there seems not to be any depending meta kernel installed. Please also show the output of:

apt-cache rdepends --important linux-image-4.15.0-115-generic

(or whichever is the latest kernel)
You seem to have some unsigned kernel installed, too, for some reason. Have you used some other tool to remove kernels besides linux-purge?