I'm guessing you're referring to
https://www.virtualbox.org/wiki/Download_Old_Builds_6_0.
That's not a formatting error: 6.0 is truly no longer supported.
Not being supported merely means no further versions will be released and no bugs will be fixed. The unsupported versions still work just fine if they used to work just fine . My production host still runs 6.0.14, and my old Windows 7 media server has 5.2.something on it.
The big change from 6.0 to 6.1 was the removal of non-hardware-vitualization-technology operation (VT-x/AMD-V). Formerly, host computers without this feature could run one-processor 32-bit VMs. From 6.1 onward all VMs require active VT-x/AMD-V. Fortunately, most if not all of the new computers of the last decade have VT-x/AMD-V, so this change does not cause trouble for the vast majority of users. 6.0 & earlier can still be run on the older computers.