Earlier quoted context omitted.
Yes those super high ones are usually freeze concentrated (partially frozen, then ice is removed which removes water, what is left is stronger) multiple times to reach such high ABVs. The highest you will see actually fermented is usually around 18-20%, but there are specialty yeasts that can get up to 25%. Then you can get even higher with extended aging in spirit barrels where some ABV is picked up by absorbing res…
Worth mentioning, freezing and skimming ice is a clever distillation process. It’s also illegal under any other circumstances that distillation would be illegal, but nobody much cares.
In the US I think it is technically illegal to make with a brewers license, though some breweries may make an Eisbock and sort of fly under the radar.