from where the packages File::Find and File::Basename are imported ?

If you are asking where the files are located on your system, perldoc will show you the full paths to those files:

perldoc -l File/Find File/Basename
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The module files (*.pm) are under the directories named in the @INC special variable, which you can inspect with:

perl -V
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Inside your code, you can also see where each use'd module comes from by inspecting the %INC special variable:

use Data::Dumper;
print Dumper(\%INC);
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Here is another good resource: Simple Module Tutorial

next unless !($file =~ m#\/Interwoven\/#);

This can be more simply written as:

  next if ($file =~ m#/Interwoven/#);
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There is no need to back-whack the slashes since you already used the alternate regex delimiters (#), and there's no need for the double-negative (unless !)