Elite Intrusion is a Codex entry featured in Tom Clancy's Rainbow Six Extraction. It was introduced in a patch on June 22nd, 2022 and is unlocked by default.
Transcript[]

INDEX Analysis:
Frequent sightings of Elite Archeans among their usual motile counterparts.
Nests can produce elites. No observable indicator to predict which Nests are producing Elites. Initial number of Elite Archeans in Sub-Zone is variable. (INSERT: Zofia - Elites still have Weak Points. Sheer numbers will not stop us.)
EXTRAPOLATIONS:
Theorizing on role in Ecosystem: May be part of an adaptive immunity to preemptively prepare defenses against foreign invaders (i.e.: Operators). Parasite increases ecosystem's overall resistance with random Elite production. Elite variants observed may indicate ecosystem health. Requires more data. (Cross-Ref: Threat level and defense response)
Speculating on factors affecting Elite Archean variant determination: Environmental factors have been ruled out. Nests have higher chance of producing an Elite. Further data required to determine stimuli. (INSERT: Capitão - About anything can be the cause. Let's focus our aim on what can be done.)
ENGAGEMENT PROTOCOLS:
Engage and neutralize before they can alert other nearby Archeans. Suggest stealth tactics and Takedowns.
If too many converge on squad's location, opt for REACT Tech and Operator Abilities to move on. Avoid prolonged engagement.