Until now, I have asked contributors to add their extension to my PopClip extensions repository on GitHub.
However, that has become unwieldy because the repository became too large and a maintenance burden (I was essentially adopting ownership of contributed extensions) so I am not currently soliciting submission there.
Right now, I’m in the process of developing a new submission flow where you would host the extension source code on your own GitHub repository, and then a mechanism to submit that to the directory. You would then keep maintenance ownership of your own extension and you would be able to update it and the directory will pull in the updates.
Please bear with me while I finish the new submission flow, and I’ll post again when it’s ready.