The su manual doesn't mention use root account by default

Hi misc@,

Greeting from me!

I read su manual (https://man.openbsd.org/su.1), but can't find words
which said if no account is provided, root is the default. But for
doas(https://man.openbsd.org/doas.1), it has following words:

-u userExecute the command as user. The default is root.

I am not a nitpicker, just curious whether I miss something? Thanks!

Best Regards
Nan Xiao