How do I fix the GPG error “NO_PUBKEY”?
I try to do sudo apt-get update and I get the following error message:
W: GPG error: http://www.openprinting.org lsb3.2 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7A4B44C2D2A2203E
There is no such repo in my sources.list
What should I do?