The error was introduced somewhere around 5.17, and was fixed in 5.35.2.

Weird. I just tried on a different machine, and didn't see the 'v' error.

$ perl -v

This is perl 5, version 30, subversion 0 (v5.30.0) built for x86_64-li
+nux-gnu-thread-multi
(with 60 registered patches, see perl -V for more detail)

Copyright 1987-2019, Larry Wall
...
$ perl -d test_email.pl

Loading DB routines from perl5db.pl version 1.55
Editor support available.

Enter h or 'h h' for help, or 'man perldebug' for more help.

IO::Socket::SSL::CODE(0x5622464f7a78)(/usr/share/perl5/IO/Socket/SSL.p
+m:330):
330:            INIT { init() }
  DB<1> f test
Choosing test_email.pl matching 'test':

  DB<2> v
1       #!/usr/bin/perl
2 
3       #  2023-0925: Test bed for sending E-Mail using the reports E-
+Mail address
4       #  under foobar.ca.
5 
6:      use DateTime;
7:      use Log::Log4perl;
  DB<2>
[download]

That's version 1.55 of the debugger ..

$ grep -m 2 VERSION /usr/share/perl/5.30/perl5db.pl
use vars qw($VERSION $header);
$VERSION = '1.55';
$
[download]

Anyway, I'm glad it was fixed, and doubly glad that Open Source exists. Imagine if this was a binary only situation -- I'd have to go back to an older version, or rely on some questionable binary patch. :/