Challenge: Complete 1,000 Core League mechanic encounters in Maps. Core League mechanics are the 10 blockable Leagues on the Atlas Passive Tree and Masters.
Extra Content is a keyword that represents content and league mechanics from previous challenge leagues that can be encountered randomly in Maps, a few of which are also encounterable in the Acts.
By default, most sources of Extra Content appear at a base chance of >8% in maps. Older mechanics may have different spawn chance calculations which have never been officially published in patch notes. This chance can be increased by various Notables and small passives on the Atlas Passive Skill Tree, or reduced to 0% through various Notables. Things that modify the rate of Extra Content do not prevent it from being spawned via guaranteed encounters e.g. Scarabs.
The Stream of Consciousness Keystone multiplies the base chance by 1.5x. In the case of mechanics with a 8% base chance, this is the same as +4% additional chance to encounter that mechanic. Note that this keystone does not affect sources of Your Maps have +#% chance to contain <league mechanic> or Your Maps have +2% chance to contain other Extra Content from the Atlas tree.
Currently, Extra Content includes the following:
| Mechanic | League | Base spawn chance |
|---|---|---|
| Abysses | Abyss league | >8% |
| Breaches | Breach league | >8% |
| Blights | Blight league | >8% |
| Expedition Encounters | Expedition league | >8% |
| Legion Encounters | Legion league | >8% |
| Metamorph Encounters | Metamorph league | >8% |
| Mirrors of Delirium | Delirium league | >8% |
| Monsters Imprisoned by Essences | Essence league | Unknown |
| Ritual Altars | Ritual league | >8% |
| Rogue exiles | Anarchy league | Unknown |
| The Sacred Grove | Harvest league | >8% |
| Shrines | Domination league | Unknown |
| Smuggler’s Caches | Heist league | Unknown |
| Strongboxes | Ambush league | 24% [a] |
| Tormented Spirits | Torment league | Unknown |
Note that content from Masters (Bestiary, Delve, Incursion, Betrayal) and other previous league mechanics (e.g. Beyond, Invasion, Rampage, Talisman, Harbinger, Warbands, Tempest, Synthesis unique maps, Ultimatum’s boss) are not considered Extra Content. Other former league mechanics that were part of the core game but were subsequently removed (e.g. Prophecy, Nemesis, Bloodlines, Archnemesis, and Perandus) are not considered “Extra Content” as well.