Seems like this won't be included with any SKUs people have bought so far—Season Pass, Ultimate, GOTY etc etc. It's only a leak so far, no official announcement, so details are hazy.
My guess from the title and achievements listed below is that it'll be a stand-alone game like…
FC3 Blood Dragon
FC4 Primal
FC5 New Dawn
…and be set in either a scifi or possibly prehistoric—eg dinosaurs—location. Looks like Danny/Dani—player character in FC6—will be in it.
Achievements:
www.trueachievements.com
My guess from the title and achievements listed below is that it'll be a stand-alone game like…
FC3 Blood Dragon
FC4 Primal
FC5 New Dawn
…and be set in either a scifi or possibly prehistoric—eg dinosaurs—location. Looks like Danny/Dani—player character in FC6—will be in it.
Achievements:
- Escape the Encasement with Fai's help
- Collect all 5 Vessel Shards
- Enter the portal and complete Fractured Fortress
- Complete 5 consecutive rifts without using glints to respawn
- Complete a run in Lost Between Worlds in 15 minute
- Take out 25 Defense Units with gadgets
- Take out 10 Defense Units with melee attacks in one run of The Maze
- Swim to a depth of 185 meters in Sunken Esperanza
- Take out 20 Defense Units in one run of Death by Darkness
- Blow up 30 Defense Units as Fai in Comandante Fai
- Complete Color Combat without Dani's health falling to a critical level

Far Cry 6: Lost Between Worlds expansion will add 11 achievements
Far Cry 6 is getting a new expansion, Lost Between Worlds, and while Ubisoft hasn't announced a launch date for it yet, the 11 achievements it will add have already gone live on the Xbox network.