/var/lib/mock contains copy of OS. It is inteded for building packages. It usually contains duplicates to what you are looking for.
E.g.
```
$ locate bash/FAQ
/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-24-x86_64-28570-30325/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-24-x86_64-28683-31985/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-24-x86_64-29477-7840/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-24-x86_64-32229-16460/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-25-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-25-x86_64-18827-15085/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-25-x86_64-27938-29561/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-25-x86_64-bootstrap-27938-29561/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-26-i386-999/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-26-i386-bootstrap-999/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-26-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-28-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-29-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-30-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-31-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-31-x86_64-bootstrap/root/usr/share/doc/bash/FAQ
/var/lib/mock/fedora-rawhide-x86_64/root/usr/share/doc/bash/FAQ
/var/lib/mock/rhelbeta-8-x86_64/root/usr/share/doc/bash/FAQ
```
- Explicitly exclude fuse.sshfs. Ideally we'd like to exclude all fuse.* file
systems, sshfs is urgent because it it can hang updatedb.
Resolves: #604145, #608094
