I you specify python3-netaddr as a stage-package in your snapcraft.yaml, the result snap will contain symlinks that point outside the snap, i.e to /var/lib/... However, if you already have python3-netaddr installed, or specify it as a build package, the same symlinks will be relative, and point to ../../../../../var/lib/... I don't see why specifying python3-netaddr as a stage-package shouldn't work out of the box. This is with snapcraft 2.42