what has winbox loader to do with passwords in export file?
export file is plain text file that holds configuration commands.
winbox loader is small tool, that connects to router and fetches dll files from router to load them as modules to display configuration of different features of your router.
please don't give your laptop, or your admin password to any other people. this will keep this file safe enough. if you are really afraid, you can use some encrypted disk software to secure this folder.
Please don't be ignorant people. There's nothing wrong with wanting a bit of security, especially these days with viruses and whatnot. I don't care what AV software you have or how smart you think you are. NO, it's NOT OK to store your passwords in clear text. Since when was that ever a good idea?