Solve the NO_PUBKEY 07DC563D1F41B907

If you add the Mozilla repository in debian Testing (mozilla.debian.net) you may get an error like this when updating with APT:

W: GPG error: http://mozilla.debian.net experimental Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 85A3D26506C4AE2A

To solve this problem you need to install the debian-keyring first

# apt-get install debian-keyring

then run these 2 commands:

# gpg --keyserver keys.gnupg.net --recv-key 06C4AE2A
# gpg -a --export 06C4AE2A | apt-key add -