It's off-brand RHEL. There's some server software that isn't compatible with any other distro. So if you wanted to run it, you either had to pay for a RHEL lice

It's off-brand RHEL. There's some server software that isn't compatible with any other distro. So if you wanted to run it, you either had to pay for a RHEL license, or run it on CentOS, which was the original official off-brand version of RHEL. Then CentOS was killed by IBM/RedHat and reborn as the beta distro for the next RHEL release. Rocky Linux and Alma Linux were created to fill this niche. For example, you can run your production server on RHEL, but run your test and dev machines on Rocky while being reasonably sure that there won't be any compatibility issues.