This archive tracks four layers. A record present in 4 of them (HH, AoI, M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
imperium
Forge world of the Mechanicum
The Machine God's own world and the Imperium's arsenal. Horus's agents split the priesthood, and the Schism of Mars turned its forges against each other before the traitor fleet ever reached Sol.
Age of the ImperiumM32–M40
imperium
Forge world; Segmentum Solar fortress
Rebuilt as the seat of the Adeptus Mechanicus and the fortress of the Segmentum Solar; the orbital shipyards known as the Ring of Iron arm the Imperial fleets.
The 41st Millenniumpre-Rift
imperium
Forge world; seat of the Adeptus Mechanicus
A red world hollowed out and rebuilt as one machine, ruled by the Fabricator-General and jealous of every scrap of surviving technology.
Era Indomituspost-Rift
imperiumImperium Sanctus
Forge world; seat of the Adeptus Mechanicus
Source of the Primaris gene-work Belisarius Cawl spent ten thousand years hiding here, and of the fleets that carried it out to the Indomitus Crusade.
Position
Map frame: 242, 522 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 259 units ≈ 27.6k light years, west of the galactic core.
Height above the disk plane: 4.8 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.