No, that's the part that works.

The part that fails is in ub fetchResources_future, which doesn't respect any base directory at all currently. There, more or less the same thing has to happen:

...
             my $duplicates;
             my $old_target = $target;
             while( $filenames{ $target }) {
                 $duplicates++;
                 ( $target = $old_target )=~ s!\.(\w+)$!_$duplicates.$
+1!;
             };
-            $names->{ $res->{url} } = $target;
+            $names->{ $res->{url} } = File::Spec->catfile( $base_dir,
+ $target );
         };
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