Comment # 43 on bug 1175342 from Michal Koutn�

Andreas, make sure you really have the updated libzypp (it took some time since
comment 32 until it reached TW repos).

I got the update only today and I can confirm it removes the cruft:
> sudo zypper purge-kernels
> [...]
> Preparing to purge obsolete kernels...
> Configuration: latest,latest-1,running
> Running kernel release: 5.9.0-rc3-2.gfd52e6c-default
> Running kernel arch: x86_64
> [...]
> 24 packages to remove.
> After the operation, 1.7 GiB will be freed