At twelfth level, a Wisdom patron Witch adds Greater Globe of Invulnerability to her spell list, which is presumably a better version of the Globe of Invulnerability spell. Unfortunately, no such spell can be found in the CRB nor Ultimate Magic. Where is this spell recorded, and why don't Wisdom witches gain the regular 6th level Globe of Invulnerability spell instead?
Greater Globe of Invulnerability doesn't exist. The designers most likely meant regular Globe of Invulnerability.
A wisdom witch would learn "Greater GoI" at the time when other patrons learn 6th level spells. I can't find any reference to this spell on any SRD or website. Furthermore, looking on Paizo's official site for the witch, the link under Globe of Invulnerability (greater) leads to the entry for the 6th level spell Globe of Invulnerability. This leads me to believe this was a misprint that was carried forward.
Given the pattern of progression from lesser to normal, once could conceive of a Greater version that is level 8 and blocks spells of 5th level and lower, but it would be homebrew.