Contributors to Github repos that have been submitted in Code Exchange are welcome and encouraged to add the "DevNet published" badge to these repos.
The way I do this is as follows.
1) Log in to Code Exchange and go to your Dashboard:
https://developer.cisco.com/codeexchange/dashboard
2) Click on any of your projects to enter the admin interface for that project, e.g.,
https://developer.cisco.com/codeexchange/github/repo/CiscoDevNet/iotvizconf#edit
Note, the link above is for one of my projects so it likely will not render for you. You will need to select one of the projects you have submitted in order to have access to its admin interface. However, the format of the URL for the admin interface of all projects is similar (i.e., https://developer.cisco.com/codeexchange/github/repo/<repo org>/<repo name>#edit )
On the right hand side you will see the helpful “Add this badge” info that you can copy/paste at the top of your README.
Admin interface for repo in Code Exchange
3) The end result in GitHub:
https://github.com/CiscoDevNet/iotvizconf
README.md in GitHub
For additional info on Code Exchange, how to submit a repo, and how to get it approved and published, check out Curated Code Repos Get Your Integration Project Done Faster, Better.