Inside the Flatpak the lenses see the host's filesystem with its /usr at
/run/host/usr - the sandbox's own /usr is the Sdk's - but not the user
and system Flatpak installations (~/.local/share/flatpak is empty inside,
/var/lib/flatpak absent), so a repository whose dependencies live in one
points its lens sections at the host's copies.
The commit-range lenses' common text (_common-repo.md) tells them where
the host's /usr is, a fact of the Flatpak rather than one repository's
convention; the kernel modes' _common.md, which says nothing of files
outside the working directory or of /usr, keeps the Python driver's
bytes. The README's sandbox notes name it, and the goldens' system text
follows.