Notice: Create a file under /and so forth/apt/sources.list.d, not the /and so on/apt/resources.checklist file in which the distribution's official repository addresses are located. That is a technique that will not destabilize your process. It is usually recommended. Extra complete display screen mode growth support on decide on displays, if https://bookmarknap.com/story6923012/5-simple-statements-about-linux-postfix-mail-server-setup-explained