Feeds for the module information of drupal.org http://simplytest.me/ has a nifty autocomplete option for the module suggestions. Screenshot attached.



I did a little digging and figured it out that ajax call being made is to the following url. 


  http://simplytest.me/simplytest/projects/autocomplete?string=views


I could be use the same end point but I need to get the permission and also the data available is not sufficient for my use case. I wanted to know if Drupal.org provides any authentic feeds of modules so that I will be able to list other details, say the download url for the tarball file.
The official Drupal.org feeds available can be found at https://www.drupal.org/api/rss.  There is a feed for projects, but to get the information about releases you'll need to parse the JSON of an API request like
https://www.drupal.org/api-d7/node.json?field_project_machine_name=media

You can read more about the APIs available and how to use them at https://www.drupal.org/api

UPDATE:  If the goal is to a list of all projects and pull their releases, this cannot be done with just an official "feed".  It requires scraping the list of projects from Drupal.org and writing code to get the release into, but the code to do that already exists.  Lin Clark's ScraperWiki code still works (http://lin-clark.com/blog/2011/07/22/writing-scripts-clone-contrib-projects-gitdrupalorg/).  Export the scrapper output as SQL, import that into a custom table, write some code to loop those the projects calling Drupal.org's API to get the release information you are looking for, and save that response.  Not as easy as just pulling the information from a feed provided by Drupal.org, but it can be done.