ほえ
$ sudo apt update
Hit:1 http:// ftp.riken.go.jp/Linux/ubuntu noble InRelease
Hit:2 http:// ftp.riken.go.jp/Linux/ubuntu noble-updates InRelease
Hit:3 http:// ftp.riken.go.jp/Linux/ubuntu noble-security InRelease
Hit:4 http:// ftp.riken.go.jp/Linux/ubuntu noble-backports InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.
N: Missing Signed-By in the sources.list(5) entry for 'http:// ftp.riken.go.jp/Linux/ubuntu'
N: Missing Signed-By in the sources.list(5) entry for 'http:// ftp.riken.go.jp/Linux/ubuntu'
N: Missing Signed-By in the sources.list(5) entry for 'http:// ftp.riken.go.jp/Linux/ubuntu'
N: Missing Signed-By in the sources.list(5) entry for 'http:// ftp.riken.go.jp/Linux/ubuntu'