While most information about a binary/source package can be found in the
control/.dsc file, all of it can be overridden when its exported to
Packages/Sources files. The extra override file contains those overrides.
The extra override file has a simple whitespace-delimited format. Comments are
allowed (denoted with a
package is the name of the binary/source package.
field-name is the name of the field that is overridden.
value is the value to put in the field. It can contain spaces as the line is split
in no more than 3 columns when its parsed.
The extra override files used to make the official Packages lists may be found
indices directory on any Debian mirror.