Bug#814156: Extra-Source-Only field in Sources index

[Ansgar Burchardt <ansgar@debian.org>]

Package: debian-policy
Severity: normal

Hi,

some time ago we introduced the "Extra-Source-Only" field in the
Sources indices generated by dak.  This field differs a bit from
regular fields as it must not appear in the source package, but is
only added by the archive software to indicate that the source is only
there to fulfill the "provide the complete source" requirement.

It can appear in these cases:

 - A binary package in suite S indicated that is was built using
   source "x (= y)" via a Built-Using field, but source package "x"
   with version "y" is not in S.

 - A binary package's source is for some reason not part of the suite:
   dak allows to remove a source package without removing its binaries.
   This usually shouldn't happen for the main archive though.

I'm not quite sure where in Policy this should be documented as it is
not used in "control files", but only added by the archive software.
Should it just be added as another field in section "5.6 List of
fields"?

Ansgar