DNS-Flag-day fail condition(s) is not clearly explained
The website states that you 'must not have timeout result in any of plain DNS and EDNS version 0 test' and in the DNS Administrators part, however in the DNS software developers part is states 'This effectivelly means that all DNS servers which do not respond at all to EDNS queries are going to be treated as dead'
Should the part for owners not be more elaborate stating the same issue combining if ALL nameservers report suchs errors and the tool only reports a FAIL if this is the case. In same events the tool reports a zone error, simply because a zone with 3 NS (dual stacked) has a only 1 nameserver with broken IPv6 will be considered broken.
So the test should say FAIL if all nameservers are really broken, or report FAIL_UNDER_CONDITIONS saying it might work now, but failure of on or more nameserver will not provide the redundancy as expected.
For more less experienced users of the tool it might be prudent to explicitly show which tests are EDNS version 0 and which are not.