Covenberth

Legendary dead moon or asteroid base setup by Joori or other Sangheili warlords after the War of Beginnings and signing of the Writ of Union. Privateers and rebels hid their ships in hollow rocks for centuries, hiding their warships as they continued on-and-off rebellions against the Covenant through the ages. "Covenberth" is one such destination, translating into UEG English of two words "coven" for a meeting place of witches and "berth" or a location where a ship makes port/repairs. As opposed to other vocabulary for such heretic fleets: "harborage" is a common term for places where Covenant stasrships are built like on Zhoist. "Vessel ossuaries" are the common term for destinations like Covenberth.
Need to look into lore of pre-Covenant ships of the Sangheili. Reference some Daybreak ship ideas and origins for the Jiralhanae.
Other terminology from a prior discussion:
*words to explore: apostate/apostatize/apostacy, coven ship, witcher/enchanter ("witcher/drone ship"), heresiarch (heretic leader) - references to witches doesn't fit Covenant religion, may require revision.
*pagans/heathens would supposedly be those from outside the Covenant religious structure in the first place (e.g. newly-contacted species) while heretics, apostates or recusants are members of Covenant species that have lapsed or abandoned the Covenant religion (with heretics specifically connoting to reformation attempts or "unacceptable" teachings)
*Apostate's End is the San Shyuum-given names to a world in the Sangheili sphere pacified in the early Covenant. The planet's population were a Sangheili sect who kept to various splinter-religions not quite aligned with the direction taken by the mainstream Sangheili who signed the writ of union. The planet's original name was scrubbed from record, and the cities razed
*Brute shamanism. Even by the time of the Covenant I expect many tribes would retain some form of native religious figure (could potentially be a way of giving female brutes something to do?) - and the Covenant may've had trouble rooting out these traditions, or sometimes had to resort to syncretism ie saying "actually your native god x is actually an expression of this Forerunner deity" etc