"Remnant" is the umbrella term coined for technology, structures, and autonomous bots that have been sighted across the Heleus Cluster. Seemingly abandoned by whomever created it, this Remnant technology is extremely advanced, but most of it is in a "standby" state. On Habitat 7, Alec Ryder discovered that reactivating this technology requires scanning "glyphs"—data packets written in Remnant coding language—and my assistance with "interfacing" at particular consoles.
This is complicated by Remnant bots that still guard and maintain many of these installations. Remnant bots do not appear to be sentient, but they are programmed to consider any interference with their technology as a hostile act, and attack single-mindedly.
The kett have an interest in Remnant technology, and have been sighted across the cluster attempting to study or control sites where it is still active. Evidence suggests the kett have not yet developed a reliable method of interfacing.
Investigations at Khi Tasira reveal that the Remnant were built by a species or faction known as the Jardaan. This technology was intended to foster life that the Jardaan had created, using the vaults to manage planetary ecology strictly, controlled from a central point known as Meridian.
The Scourge destroyed the connection from Meridian to these vaults and deactivated many of the Jardaan's technological creations. The Jardaan left the cluster soon afterwards for an unknown location, leaving their technology behind as remnants of their civilization in Heleus.