Dan Scavino tweet is a nod to JFK.
The flag was presented to JFK by the Army on Dec 17th, 1962 in the oval office. The flag was placed behind his desk, where POTUS also has it displayed. POTUS redecorated the Oval after BHO, bringing back the military flags to symbolize how much he loves our military.
Could have a deeper meaning, but start here with JFK connection..
https://historyinpieces.com/video/footage/jfk-presented-army-flag-oval-office
https://jfk14thday.com/presidents-daily-diary-december-1962/
I'm posting again from last bread