Precursor Nanotech
The Precursors developed a unique and highly powerful form of nanotechnology made out of galraite, which was intrinsically entangled with the Substrate in order to allow its users control over reality itself. The technology was used to build supercomputers and consciousness manipulation technology, and even served as bodies for the Precursors themselves.
Activation
The nanotech was theorised to originally be "living technology", reconfiguring itself at the will of the user. All currently recovered Precursor artefacts built out of nanotech are said to be "dead"; they retain their architecture and connection to the Substrate, but the nanites themselves are permanently inert, which means the artefacts can be used in their last configuration but can no longer be reconfigured.
This is due to the substratic antipattern known as The Erosion which wiped out the Precursors, as well as the sentient neural matrices within their nanites. Theoretically, recovered Precursor technology with active, intact nanites would allow one almost godlike powers over their surroundings, but the existence of any such technology is said to be near-impossible.