This summary is not the rule. The rule text controls.
A legal intern who is still working toward their law license cannot argue a case in front of an appeals court alone. If the case is being appealed, whether it's a criminal case or a civil one, the intern must have an approved supervising attorney with them in the courtroom.
This rule exists to make sure someone with a full law license is there to guide and support the intern during appellate cases. Appeals often involve tricky legal arguments, so the supervising attorney's presence protects the people involved in the case and makes sure the intern isn't handling things beyond their training on their own.
If you're involved in a case that gets appealed and a legal intern is helping with your case, you can expect a licensed, supervising attorney to also be present in court. The intern cannot show up alone to represent you at this stage.