Release file entry (Origin, Label, Codename, etc.) in the format of
APT_PREFERENCES(5).
+- **Source:** (optional) The name of the source package the binary
+ package this record is for was built from.
+ This field does NOT include the version of the source package unlike
+ the Source field in the dpkg database. The version is optionally
+ available in the **Source-Version:** field.
+
### Answer