From Halopedia, the Halo wiki
Crew and complement
During the Forerunner-Flood war the Ancillas tasked with controlled the vessels proved to be remarkably resistant to the Logic plague however they were ill-prepared to counter the used of infected Forerunners as shields and traps by the Gravemind. Many battlecruiser were captured by the Flood with their ancillas twisted into rampancy.
The design of the Skirr-class used in the Halo Encyclopedia (2022 edition) is unused concept development artwork produced by Chuck Wojtkiewicz for Blur Studio during the production of Halo Wars. The design was produced as part of concept explorations for the Sojourner-class dreadnought.