Per-phase status map. Phases not yet reached are absent (treated as 'pending').
OptionalResolvedConcrete release tag the scaffold phase resolved Tag to (e.g. "v6.1.2"
when Tag is "latest"). Absent until scaffold completes. Persisted so a
resumed install pins the same version as the scaffolded code.
ISO 8601 timestamp when the install was started.
Git tag of the version being installed (e.g., "v5.1.0").
Serialized shape of the
.mj-install-state.jsoncheckpoint file. This is the on-disk JSON structure read by InstallState.Load and written by InstallState.Save.