The UCI allows teams one kit switch-out per season. For some teams, like Jumbo-Visma, this is a right reserved for the Tour de France Femmes, where the riders' yellow jerseys would obviously detract from the famous maillot jaune. The same situation arises for EF Education at the Giro d'Italia.
For other teams, it can be down to a new sponsor arrangement, which often tends to occur at the Tour de France as this is the biggest stage. Finally, for others, it's simply a chance to make a splash and line up against the best riders in the world with some fresh kit.
