Which uninstalled package provides a file?

$ apt-file find guestmount
guestmount: /usr/bin/guestmount
guestmount: /usr/share/bash-completion/completions/guestmount
guestmount: /usr/share/doc/guestmount/changelog.Debian.gz
guestmount: /usr/share/doc/guestmount/copyright
guestmount: /usr/share/man/ja/man1/guestmount.1.gz
guestmount: /usr/share/man/man1/guestmount.1.gz
guestmount: /usr/share/man/uk/man1/guestmount.1.gz

Which APT repository did a package come from?

$ apt policy wget
wget:
  Installed: 1.21.2-2ubuntu1
  Candidate: 1.21.2-2ubuntu1
  Version table:
 *** 1.21.2-2ubuntu1 500
        500 http://gb.archive.ubuntu.com/ubuntu jammy/main amd64 Packages
        100 /var/lib/dpkg/status