Currently, Prologue Quests are categorised in the Journal under one of the zones they take place in - The Missing Prophecy in Stormhaven, Of Knives and Long Shadows in Deshaan, Through a Veil Darkly in Glenumbra, etc. Since these quests take you all across Tamriel, it is a bit inconsistent to tie them to a specific zone, especially when all other zone quests are entirely contained within the relevant zone. Some zones could even be considered more appropriate than the one they were assigned to; Through a Veil Darkly, for example, potentially has a stronger connection to Auridon than it does to Glenumbra.

For Prologue Quests to be more consistent, both with each other, and with the rest of the quests that span Tamriel (like Guild quests, Holiday Events and other Miscellaneous), I think they should be given their own Prologues category in the Journal. This would also help to identify them better for players so that they can clearly see it's a Prologue rather than another generic Side Quest in the zone.

An alternative to putting them all in a Prologues category would be to put each one in the zone category for the zone they are teasing - The Missing Prophecy for Vvardenfell, Of Knives and Long Shadows for Clockwork City, etc. (Bonus points if they then get added to the Zone Story for that zone, since they are related to it...)