The technique that is typically found in a non-linear plot structure but not in a linear plot structure is flashback.
In a linear plot structure, events are presented in chronological order, following a straightforward timeline from beginning to end. Non-linear plot structures, on the other hand, often employ flashbacks (or flash-forwards) to present past or future events out of the chronological sequence, allowing for a more complex narrative.
While cliffhangers and conflict resolution can occur in both linear and non-linear structures, chronological order is a defining characteristic of a linear plot.