Mercatus Assembler Vats
From Halopedia, the Halo wiki
The Mercatus Assembler Vats were a type of assembler vat technology used throughout the Forerunner Ecumene. The Mercatus vats consisted of the massive industrial vaults and resource processing facilities dedicated to the construction of all mechanisms and structures used in everyday Forerunner civilian life. They had an extraordinarily high output, limited only by security restrictions and local demand.
- Halo Encyclopedia (2022 edition), page 325