Which filesystems can share blocks

A filesystem missing from this table is measured like any other, so the answer comes from the probe.

System	Works	Does not
macOS	APFS	HFS+, exFAT
Linux	btrfs, XFS with `reflink=1`, OpenZFS 2.2+, bcachefs	ext4, tmpfs, f2fs

A filesystem missing from this table is measured like any other, so the answer comes from the probe.

What a clone cannot carry

Absolute paths inside files that `doctor` does not know the format of. A compiled artifact with a build path baked into it, a database with a stored data directory, a lockfile that recorded where it ran. They are copied faithfully and they still name the original.