Browsers such as Firefox, Chromium, and Safari prefer bare IPv6 addresses in
CNs. They generate confusing errors when they see bracketed CNs. For example:
You attempted to reach [2001:470:1:18::120], but instead you actually reached
a server identifying itself as [2001:470:1:18::120]. Chromium can say for sure
that you reached [2001:470:1:18::120], but cannot verify that that is the same
site as [2001:470:1:18::120] which you intended to reach.