Consti

Not quite correct. For html, that is to signal standard compliance, you can leave it away and the browser will still handle it. For the bash one, all (most) shell scripts use .sh, so you need to give a shebang to tell the loader which executable (sh, bash, zsh, csh, …) to use

Also on Linux xdg does take file extensions into account, just executables do not

Eine Minute später kommt der Zug, der vor zwei Stunden kommen hätte sollen, neues Problem

Pretty sure the commenter above meant that the their RAM was advertised as X GiB but they only got X GB, substitute X with 4/8/16/your amount