Makes sense. I'm not familiar with Fossil, but I know trunk was also the standard when I used SVN back in the day. I think the trunk-branch metaphor makes more sense in the centralized VCS model where there is actually something special about the trunk that makes it distinct from branches, whereas in a DVCS like git master is just another branch except that it happens to be the default one checked out.

Ultimately, it doesn't matter to me in and of itself. Even before last year, it wasn't that unusual to see git/GitHub repos with default branch names other than master (dev is probably the next most common one I've seen), and presumably not because of anything to do with racial justice. "Master" seems most practical to me for the moment, since it's the most standard/common term and is relatively non-overloaded, whereas "main" may be more ambiguous unless expanded to "the main branch" (depending on context).

It almost feels silly to bikeshed about something so minor, but it's not fair for anyone to demand that millions of people change their behavior and/or spend money without meeting some reasonable burden of proof. It's a slippery slope to allowing such unfalsifiable Pascal's-wager-type propositions ("foo may or may not be harmful, so better do bar instead just in case") to be used for more malicious manipulation of markets and geopolitics.