apt-get update
Hit:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Ign:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Hit:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Ign:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Hit:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Hit:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Fetched 819 B in 1s (1,143 B/s)
Reading package lists... Done
W: GPG error: http://dl.google.com/linux/mod-pagespeed/deb stable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 78BD65473CB3BD13
wget -q -O - https://dl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
OK
apt-get update
Hit:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Ign:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Hit:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Ign:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Hit:9 http://dl.google.com/linux/mod-pagespeed/deb stable/main amd64 Packages
Hit:10 http://dl.google.com/linux/mod-pagespeed/deb stable/main i386 Packages
Hit:11 http://security.ubuntu.com/ubuntu bionic-security InRelease
Fetched 2,973 B in 1s (4,169 B/s)
Reading package lists... Done