This summary is not the rule. The rule text controls.
If you're facing criminal charges, you sometimes want to challenge a decision the judge made before trial, like a ruling on evidence or a motion to suppress. Normally, pleading guilty gives up your right to appeal those kinds of decisions. This rule gives you another option.
You can enter what's called a conditional guilty plea. This means you plead guilty, but you and the court agree in writing that you're keeping the right to appeal one specific ruling the judge made earlier in the case. The judge has to approve this arrangement before it can happen.
If you appeal and win, meaning the appeals court agrees the earlier ruling was wrong, you get to take back your guilty plea. This protects you from being stuck with a guilty plea based on a decision that turns out to be legally incorrect. It also means you don't have to go through a full trial just to preserve your right to challenge that one ruling.