Hi Amanda! You probably read about the Race Retreat tent.
The Race Retreat tent is something you can purchase as an extra to use on race morning. It is a climate controlled tent with tables, chairs, and sofas. There will be pre-race food and drinks, computers for runner tracking, TV's, character greetings, private bathrooms, and a private bag check. It is a little expensive, but I always buy it. I like to get to the race early, and having a warm place to sit and all of the other amenities makes it worth the extra cost.
You can also return to the tent after the race for hot food and massages. You can find more information about on the
Walt Disney World Marathon website. Just click on "Event Overview" and then "Race Retreat" in the left column.
I hope this is what you were looking for! Please let me know if you have any other questions!