Defined in /home/build/jenkins/workspace/RockBootstrap19/FLAVOR/master/label/DebianUnstable/dev/autoproj/remotes/rock/rock.osdeps as

libkdtree:
    debian,ubuntu:
        default: libkdtree++-dev
        '12.10': nonexistent
      gentoo: libkdtree++
      fedora: nonexistent