No announcement, no intentions, no hidden meanings or messages. Just a nice note.
"I want to thank BYU, its fans, its coaches, its administration, and its educators. BYU truly is a special place, and one I'll always remember fondly. With that being said, have a wonderful day, Cougar nation!"
I think if I were an athlete I'd have a lot of fun creating graphics with nice messages on them and blasting them out all over my social media.