W: The repository 'http://ppa.launchpad.net/heathbar/super-wingpanel-daily/ubuntu xenial Release' does not have a Release file.
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.
E: Failed to fetch http://ppa.launchpad.net/heathbar/super-wingpanel-daily/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
$ sudo apt-get install super-wingpanel
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package super-wingpanel
答案1
如果您查看 launchpad 网站，您会发现 super-wingpanel 仅适用于 Ubuntu Precise - 没有适用于 Ubuntu Xenial 的版本。该软件包三年来一直没有更新。
