Getting grubby with ZFS

As another example, Bazaar is GNU but its copyright is assigned to Canonical. The Canonical contributor agreement that you have to sign to get code into GNU Bazaar even expressly allows for your contribution to be used in proprietary software.

So the FSF is indeed flexible when it wants to be.

(FWIW, I consider the bzr case to be a fairly important error that needs to be corrected.)