GNU ed in the RRS has an unknown version upgrade (http://recipes.yoctoproject.org/rrs/recipedetail/351/) but the http index should be trivially indexable (http://ftp.gnu.org/gnu/ed/). I suspect the problem is that all of the tarballs as .tar.lz, and we don't handle that extension in bitbake.
This is apparently no longer an issue, as the ed recipe now shows up as "up-to-date". The RRS itself has no references to tarball types. tar.lz has been handed in bitbake since 2014 but only recently in 2017 we added lzip-native to support unpacking it, and subsequently updated the ed recipe to point to the upstream tar.lz file, so I suspect that was what resolved it.