What is "superefficient"

Usage examples of "superefficient".

Then he reluctantly puttered into the muniments room, where the superefficient librarian had already got out the Stonehouse dossiers for him and put them on a table by the open doors, and sat down to read.

Even an advanced and superefficient temporal-confinement system was a massive power hog, and so the confinement chamber was built as small as possible.