ArmBase
data class ArmBase(val capsule: Capsule, val command: String, val environment: Environment, val digests: Map<String, String> = emptyMap(), val envNames: Set<String> = emptySet())(source)
The configuration both arms start from: a capsule, the failing command, where it runs, and the env names run.sh mirrors beyond the allowlist (so a variable under test is in the control).