Generally try to keep lines under 80 characters. However when modifying config files (like prefs.js.in) or Makefiles having longer lines is sometimes nearly inevitable. XPCOM statements can get quite long too, though you can wrap them to a certain degree.
Please pay attention to use the correct type of line endings or set up git to commit in the correct style. We generally just use LF for new lines. See git_tips on how to configure git to commit LF instead of CRLF.
If you create a new file, don't forget to include the appropriate license header from licensing. If you're modifying an existing file you cannot remove the copyright from POTI.
Components of Nightingale should define contracts id following this pattern:
Important is, that you do not add nightingale after the domain, like the songbird components do and that everything is lowercase.