Identifying Community Modules vs. Custom Modules Is there a list of Drupal Community modules that's easily query-able by the module's name/folder-name?

Context: I've inherited a web application built in Drupal.  This application has around 30 modules in 

sites/all/modules


I'd like to identify which modules the previous team developed on their own vs. which modules the previous team downloaded from the community modules listing.  

So, I'm looking for a list of community modules I could check the module identifier (as opposed it's free form name) against in an automated way.  This seems easier than manually search for 30 different modules.  

Happy to hear other solutions for my problem.
I am unaware of any full list of modules that are on drupal.org for public consumption (there are a lot).  If I were you, I would do one of two approaches.

Based on https://stackoverflow.com/questions/6136022

cd sites/all/modules
for module in *; do
  echo -n $module
  echo -n ': '
  wget --spider --no-check-certificate -S "https://drupal.org/project/$module" 2&gt;&amp;1 | grep "HTTP/" | awk '{print $2}'
done


Lines that print out with a 200 exists; ones that don't should give a 404.

The other option is  

cd sites/all/modules
for module in *; do
  grep 'project = ' $i/$i.info
done


Only modules on drupal.org will have a project line, which gets added by the packager script.

Also, if you visit the Available Updates page (admin/reports/updates) and check for updates, only public modules will be listed.