From the basic installation page:

https://docs.projectquay.io/deploy_quay.html

"For a Project Quay Registry installation (appropriate for non-production purposes), you need one system (physical or virtual machine) that has the following attributes:

    Red Hat Enterprise Linux (RHEL): Obtain the latest Red Hat Enterprise Linux server media from the Downloads page and follow instructions from the Red Hat Enterprise Linux 7 Installation Guide.

    Valid Red Hat Subscription: Obtain a valid Red Hat Enterprise Linux server subscription.

"

So, is it truly tied to RHEL and a subscription, or is that page just making me FEEL that way?

Annoying either way. :/