When and under what conditions does a project become public and listed in "Public Projects" in oTree Hub?

In the past, I tried to deploy my app with otree server deployment system, but failed.
So, I have deployed my app without otree server deployment system. In detail, I downloaded otreezip file from studio, edited it with VSCode and uploaded it to github. Then I connected github repository to my heroku account. I have already finished my experiment. 

Now I want to cancel my otree hub subscription, but in Account tab, I found this message: 

About Server Deployment
Once you have built your application, whether you used oTree Studio or not, you can use our server deployment system to easily deploy your application on a Heroku web server. The Pro plan allows you to manage 8 sites simultaneously. (Without a subscription, you can still deploy to Heroku, but your site and source code will be publicly available here.)

Now my app is not listed in "Public projects"
I do not want my app to be public.

it won't change to public, even if your subscription is changed.

I appreciate your reply. I understand.