HP plugin installation does not work properly, HPLIP 3.16.11

I recently tried to configure my notebook for the use with a HP Color Laser Jet Pro MFP M277n all-in-one device.
This needs the ominous software plugin. It turned out to be cumbersome, but in the end I had success with a workaround.

Here is what I did:

  1. Trying with YAST>Hardware>Printer, launching hp-setup from the second dialog. After a long time waiting in the third dialog with lots of CPU activity I killed the processes.

  2. run

# hp-setup

from the command line. This tells me that I have to run hp-plugin as a user.

  1. Running
> hp-plugin 

HP Linux Imaging and Printing System (ver. 3.16.11)
Plugin Download and Install Utility ver. 2.1


Checking for network connection...
Downloading plug-in from: 
error: Plugin download failed with error code = 8
Traceback (most recent call last):
  File "/usr/share/hplip/ui4/plugindialog.py", line 260, in NextButton_clicked
  File "/usr/share/hplip/installer/pluginhandler.py", line 474, in deleteInstallationFiles
OSError: [Errno 21] Ist ein Verzeichnis: '.asc'
  1. Googling this error led me to the following solution: Download the files
[hplip-3.16.11-plugin.run  hplip-3.16.11-plugin.run.asc/CODE]
from [https://www.openprinting.org/download/printdriver/auxfiles/HP/plugins](https://www.openprinting.org/download/printdriver/auxfiles/HP/plugins)run 


 again. Select install from local source from the appearing dialog. Ignore the warning about missing key ("install anyway"). This led to successfull
plugin installation. Then run 


 once again. Finally printing and scanning works as expected, but with the stale taste of an insecure installation.