Jax speaks with a British accent. It is the natural accent of actor Franz Drameh, who previously used an American accent while playing Jax.
This is the 100th episode.
Kendra Saunders (Hawkgirl) is the only founding member of the Legends to not make an appearance. However, Mick Rory (Heat Wave), who's also a member of the original team, only appears through archive footage and lying down portrayed by a stunt double.
Sharp-eyed fans will recognize the farm as the Kent Farm from Smallville. It's hard to mistake the yellow house after seeing in so many seasons of the show.
This was originally titled "WVRDR_ERROR_100 (Oest-of-th3-Gs.gid30n) notFound," as seen on the title page of its script. This title, sans the brackets, could also be seen on The CW's website. The title translates to "Waverider Error 100, Oldest of the G's Gideon not found."