How I arrived at the problem

1. Used NAPS2 to do scanning using an old Microtek 4900 scanner.  It worked with windows.
2. Switched to Ubuntu Linux ( Windows 11 insufferable ) 
3. I tried using NAPS2 to run a Microtek scanner but it did not support that model under Linux.  Installed NAPS2 and it did not work
4. Removed NAPS2
5. Every time I did a repository update:   sudo apt update – I was flagged with a problem updating the NAPS2 repository
6. Since NAPS2 had been de-installed I wanted to remove the repository from the list of things that would be updated by apt update
7. Standard explanation to use "Software & Updates" list by unchecking the item did not apply because download.naps2.stuff was not in the list
8. Solution:   Went to the directory shown below and deleted the NAPS2 file.  
9. sudo apt update –> no longer showed the repository error.

 

 

Which leads into the next set of gripes:   ( have not executed / tested this process yet )

• G: repository can not be updated legacy keyring 
• AskUbuntu: apt-key deprecation warning when updating system: "Key is stored in legacy trusted.gpg keyring"    – this shows the steps to bring the keys into the newer form. 

 

Additional Errors Seen

• The following signatures couldn't be verified because the public key is not available
• doesn't support architecture 'i386'

 

Errors flagged by sudo apt update