It looks like you've revealed my evil action :) But, it seems like your method will also need hardcoding at least in two places. I'm currently using PerlSetVar to set the location:

<Location /foo>
SetHandler perl-script
PerlSetVar NAME "/foo"
PerlHandler My::Apache::Handler
</Location>
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It looks like Apache2::Directive may help, but I still need to know what the location is:

  use Apache2::Directive ();
  my $tree = Apache2::Directive::conftree();
  my $node = $tree->lookup('Location', '/foo/');
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