Feebs is now atlassian-connect-express.
Updating your existing add-on
If you've created an addon feebs, you can upgrade your addon to use the atlassian-connect-express library simply by changing the feebs dependencies reference in your package.json to atlassian-connect-express:
...
"atlassian-connect-express": "~0.6.0"
...
Also, anywhere you reference a FEEBS_* environment variable, change it to AC_*.
Contributing
If you wish to see the code, the new repo is at atlassian-connect-express.