It's just someone's typo but its a really good idea. You can create your own custom steps and this person didn't want to forget to put their wort chiller in the boil kettle at the the last 15 minutes to sanitize it. I have a similar step in my profile along with reminders to add Whirfloc and yeast nutrient. These show up in your timer on brew day and are a handy reminder so that you don't miss crucial steps.