Copyright of debian/*

[Matthew Vernon <matthew@debian.org>]

Hi,

I have noticed some packages using the newer machine-readable copyright 
format, but not specifying any copyright for debian/*

To give an example based on the docs[1]

Files: *
Copyright: 1975-2010 Ulla Upstream
License: GPL-2+

Files: docs/*.1
Copyright: 2010 Manuela Manpager
License: GPL-2+

Let us assume that Ulla Upstream has nothing to do with the contents of 
debian/* (and that e.g. the git history lets us be sure of that).

What does that mean about the copyright status of debian/* ? If I want 
to re-use a file therein in another package, can I do so?

Thanks,

Matthew

[1] https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/