Disney's Hollywood Studios is adjusting their park hours due to the popularity of the new Star Wars: Rise of the Resistance attraction. Starting on December 9, 2019 Disney's Hollywood Studios will open at 8:00 AM every day except when Extra Magic Hours is offered on Sundays. Disney's Hollywood Studios' earlier opening will last until January 4, 2020.
Extra Magic Hours is a perk for guest of Disney Resorts and other hotels to spend extra time in one of the theme parks each day before it opens or closes. For Disney's Hollywood Studios it is offered on Sunday and allows guests to enter an hour earlier (except for December 8 which allows guests to enter at 6 AM!)