the Linux/Ubuntu release for the DB410c are "based on Ubuntu". The current releases for DB410c (both 15.06 and 15.07) are based on Ubuntu 15.04 release (aka vivid). It's a bit confusing that our naming policy is very similar from the Ubuntu one, I agree..
There is no way currently to retrieve which Linaro release is running at run time on the target. I think you only get this information when you download or in the installer.
If you run "lsb_release -a" it will return Ubuntu 15.04. Maybe we should add the Linaro build info somewhere in the file system, but that's not so simple ...
... because a user can use apt-get update/upgrade to get package updates. In which case a user would get updates from Ubuntu or also potentially updates from Linaro packages. And in that case the release running on the target no longer is an official release from us.
Our images are assembled by downloading packages (Debian packages) from the Ubuntu archives (vivid archives currently) and from the Linaro archive (http://repo.linaro.org/ubuntu/). We have new image builds regularly , either on-demand or when the kernel changes. The build number such as (#80) corresponds to a unique build on our build server (e.g. https://ci.linaro.org/view/member-builds/job/lt-qcom-ubuntu-images-arm64/80/).
Our builds are first exported to http://builds.96boards.org/snapshots/dragonboard410c/linaro/ubuntu/, and when a build is deemed good enough and it's time to make a release, we copy it to http://builds.96boards.org/releases/dragonboard410c/linaro/ubuntu/, with a 'pretty' name. That's why you see it twice. But you can be sure that the build ID is unique, so #80 really represents the same build where you got it from the 'snapshots' or the 'releases' areas.