How can I show an additional column in Dired, where I can see if the file is tracked or not by git in the current branch?
You might want to look at diff-hl and this answer on Stack Exchange. Basically, diff-hl puts the git status of files in a dir in the margin rather than in the column. Depending on what exactly you're looking for, this should suffice. Just add the
diff-hl package, and use
(add-hook 'dired-mode-hook 'diff-hl-dired-mode)