Fives's new helmet has an image of an Rishi Eel, the same creature that attacked his squad in Rookies (2008).
First appearance of Phase Two Clone helmets and armor (as seen in Star Wars: Episode III - Revenge of the Sith (2005)). Captain Rex wears a unique version, he is still wearing his Phase One helmet, with the new Phase Two chin piece welded onto it. The weld-marks are visible in close-ups.
The 2020 anthology book "Star Wars The Clone Wars: Stories of Light and Dark" features a story based on all four parts of the Umbara arc that is told from Rex's point of view. It is written by Yoon Ha Lee and titled "The Shadow of Umbara". The audio-book version is read by Clone Wars voice actor James Arnold Taylor.
During the 'newsreel' sequence that opens the show, Ahsoka Tana and Barriss Offee are briefly seen taking part in the space battle, piloting Jedi Starfighters.
The 'Jedi fortune cookie' message that opens the show reads "The first step towards loyalty is trust."