The override file has a simple whitespace-delimited format. Comments are allowed (denoted with a #).
package priority section [maintainerinfo]
package is the name of the package. Entries in the override file for packages not found in the tree of binary packages are ignored.
priority and section correspond to the respective control fields available in the .deb. The allowed values are specific to each distribution archive.
maintainerinfo, if present, can be either the name of a maintainer for an unconditional override, or else oldmaintainer => newmaintainer to perform a substitution.