GRB 211211A and the emerging class of long GRBs from mergers

This concise review places GRB 211211A at the center of a discussion on the association between long gamma-ray bursts and kilonovae, and on the central engines capable of powering extended emission. We present the key observations, compare prompt and extended emission models, evaluate kilonova interpretations (r-process vs engine-powered vs jet–ejecta heating), and discuss central engine scenarios (magnetar vs black hole + fallback). Figures and a parameter table illustrate a hybrid engine + r-process model that qualitatively reproduces the observed behaviour.