The manual page contains an error in the FILES section. It states that the configuration file is in @sysconfdir@/stunnel/stunnel.conf. Correctly, the @sysconfdir@ should be replaced by an expansion of %%PREFIX%%/etc.
The fix has been done in stunnel-5.59,1.
By the way, is this security/stunnel instead of sysutils?
My apologies. Yes, it is.
Just to be clear, it's fixed now?