Oh wow, I clicked on that link on mobile and was unable to go back. Pressing the back button just redirected to the same page over and over again. Usually you only see that on malicious ad sites.
EF 6 had an interesting take on this problem. If two migrations had the same parent (aka we both branched and added a migration), whoever merged second would have to generate a "merge" migration to resolve the conflict. It wasn't the most elegant solution, or even a solution period, but it made the problem explicit. This happened because the full schema model was serialized and encoded into the migration journal table.