root@debian:~# apt-get update
Ign http://ftp.us.debian.org jessie InRelease
Hit http://ftp.us.debian.org jessie-updates InRelease
Ign http://ppa.launchpad.net jessie InRelease
Hit http://ftp.us.debian.org jessie Release.gpg
Hit http://ftp.us.debian.org jessie Release
Hit http://security.debian.org jessie/updates InRelease
Ign http://ppa.launchpad.net jessie Release.gpg
Get:1 http://ftp.us.debian.org jessie-updates/main amd64 Packages/DiffIndex [7,900 B]
Get:2 http://ftp.us.debian.org jessie-updates/main Translation-en/DiffIndex [2,704 B]
Ign http://ppa.launchpad.net jessie Release
Hit http://ftp.us.debian.org jessie-updates/main Sources
Hit http://ftp.us.debian.org jessie/main Sources
Hit http://ftp.us.debian.org jessie/main amd64 Packages
Hit http://security.debian.org jessie/updates/main Sources
Hit http://ftp.us.debian.org jessie/main Translation-en
Hit http://security.debian.org jessie/updates/main amd64 Packages
Hit http://security.debian.org jessie/updates/main Translation-en
Err http://ppa.launchpad.net jessie/main amd64 Packages
  404  Not Found
Ign http://ppa.launchpad.net jessie/main Translation-en_US
Ign http://ppa.launchpad.net jessie/main Translation-en
Fetched 10.6 kB in 1s (6,145 B/s)
W: Failed to fetch http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu/dists/jessie/main/binary-amd64/Packages  404  Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.
root@debian:~#