Firefox follows a convention where the actual binary is firefox-bin and launcher is just firefox. Lots of other nix apps do this, especially statically linked apps. If I had seen crayon-bin and crayon, I would have tried crayon first; however, I just read the ls until crayon and launched that directly, only seeing launcher on second examination. I know that you're not supposed to launch x-bin directly, it usually has a launcher script named just x.