@pettter Just done that, and have this:
# ls /etc/apt/sources.list.d | cat
alex-p-ubuntu-tesseract-ocr5-focal.list
alex-p-ubuntu-tesseract-ocr-focal.list
alex-p-ubuntu-tesseract-ocr-focal.list.save
google-chrome.list
google-chrome.sources
linrunner-ubuntu-tlp-focal.list
linrunner-ubuntu-tlp-focal.list.save
signal-xenial.list
signal-xenial.list.save
skype-stable.list
skype-stable.list.save
ubuntu-esm-apps.list
ubuntu-esm-infra.list
In particular:
# ls /etc/apt/sources.list.d/sk* | cat
/etc/apt/sources.list.d/skype-stable.list
/etc/apt/sources.list.d/skype-stable.list.save
Should I just delete those files?