The ground check cable is used in conjunction with a meter to determine if the grounding path has become impaired due to mechanical action/ pulling tension.
The logic is similar to a hospital setting: the grounding path must be perfect at all times to avoid a catastrophic spark.
The pdf lists the ohms per foot of the various cables. Any deviations from factory spec indicate a degraded grounding path. Continuous monitoring from the source end would permit the circuit to be de-energized the instant something went awry.