So should GNU maintainers add copyright lines to CC0d files? what
about non-gnu Savannah programs? which recommendation applies to them?
what should the hosting requirement be (we routinely point
to GNU Maintainer Info to tell how software should be packaged)?
I don't think GNU programs should have any non-trivial files CC0.
And even for that the GNU project has guidelines:
https://www.gnu.org/prep/maintain/maintain.html#License-Notices-for-Other-Files
