To optimize the spring from the Board feet should be around shoulder width apart. Brenna could be faster bringing her feet together in preflight, however.
It’s not easy for judges to see that foot separation at full speed.
Don’t count on everything in that post being exactly correct. There are so many changes that I anticipate future clarifications for years to come.
Personally I’m happy that FIG gymnasts no longer feel pressured to do a D dismount as dismount is no longer a 0.5 Special Requirement. Sticking a C dismount will be the best strategy for many around the world.