These are terms that are referenced in the NSS error codes.
Beasts is the name NSS gives to the objects it supports. Beasts include objects such as files, directories, volumes, data streams or extended attributes.
A checkpoint is a record written to the log and is used to verify the integrity of the log.
A designated number used to verify that the checkpoint log record is not corrupt.
A superblock is known and fixed areas of the disk where file system specific information is stored.