STELTEK

The Steltek are an advanced species which developed a galaxy-spanning empire 2.4 billion years ago. They eventually retreated from the galaxy, after bringing ruin upon themselves with their technology, possibly in a civil war. Before leaving, the Steltek attempted to destroy all of their technology so that developing races would not bring the same ruin upon themselves. However, some artefacts still remain. The Steltek eliminate these pockets when possible.
Source: Wing COmmander Universe.