@Corion Thanks very much for the reply.

Now what is the easiest way to fix this?

Can anyone see a problem with simply taking this list of all the installed perl modules and running apt reinstall list-of-modules

You mentioned "XS" -- does that have any connection to xs in the module names (in my list)? Would just reinstalling those fix the issue?

What about perlbrew? I have perlbrew installed.

Do perlbrew config files contain any important data that needs to be preserved? (Other than a list of installed modules?)

How can I compile a list of any modules that are installed in perlbrew?

It seems to me that this should be a mechanical process to recreate a fresh installation, or am I missing something?

Thanks again for the assist!