Wie kann ich diese Nachricht ignorieren?
W: GPG error: https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 56A3DEF863961D39
W: The repository 'https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
Es ist von Intel Update GFX.
download.01.org
. Sie werden nur Ärger bekommen.