Found some documentation listing the two middle switches as the rounding switch (up fraction down) and the decimal switch (auto? 0 to 6 then hex?). No idea on the other two.

http://www.calcuseum.com/SCRAPBOOK/BONUS/32853/1.htm

Decimal switch: [A-0-2-3-4-6-F], Round switch: [(ArrowUp)-5/4-(ArrowDown)], Miscellaneous switch: [(Blank)-K .-(Sigma)],

The DNS-01 challenge can be used to generate a wildcard by creating the requested dns record in your public dns zone, then you can use that cert for internal servers/dns. With certain dns providers it can even be automated.

https://eff-certbot.readthedocs.io/en/stable/using.html#third-party-plugins