classRename

Build the rename, or null when this runtime renames no classes.

Fabric production and spigot both rename CLASSES — class_2338 and BlockPosition for the same BlockPos. Forge Mixed-SRG does not: it obfuscates members only, so its rows are identities — dropped below, leaving an empty table and a null that keeps that runtime on the overlay's untouched copy path.

Reads the bundle's mappings FILE rather than the Mappings singleton: the file is on disk as soon as RemapBundle publishes, so this inherits buildClasspath's existing remap dependency and opens no new window.