cd /etc/apt/sources.list.d
It's all here.
Drwxr-xr-x 2 root root 4096 May 23:41/drwxr-xr-x 6 root root 4096 May 20 20:59.. /-rw-r--r--1 root root 216 May 23:41 daniruiz-ubuntu-flat-remix-bionic.list-rw-r--r--1 root root 216 May 23:41 D aniruiz-ubuntu-flat-remix-bionic.list.save-rw-r--r--1 root root 154 May 22 23:41 dyatlov-igor-ubuntu-sierra-theme-bionic.list-rw-r--r--1 root root 154 May 22 23:41 dyatlov-igor-ubuntu-sierra-theme-bionic.list.save-rw-r--r--1 root root 189 May 23:41 google-chrome.list-rw-r--r--1 R Oot root 189 May 23:41 google-chrome.list.save-rw-r--r--1 root root 192 May 23:41 shutter-ubuntu-ppa-bionic.list- rw-r--r--1 root root 126 May 23:41 shutter-ubuntu-ppa-bionic.list.save-rw-r--r--1 root root 65 May 23:41 Sogoup inyin.list-rw-r--r--1 root root 65 May 23:41 sogoupinyin.list.save-rw-r--r--1 root root 128 May 23:41 system76- ubuntu-pop-bionic.list-rw-r--r--1 root root 128 May 23:41 system76-ubuntu-pop-bionic.list.save-rw-r--r--1 root root 193 May 22 23: vscode.list-rw-r--r--1 root root 193 May 23:41 Vscode.list.save
Ubuntu Delete PPA source