Some people are habituated to keep their passwords in a plain text log file. They don't even bother to encrypt that file. They might not have thouight how much dangerous is it to do such a stupid task. The consequence is that - Some n00b can just access that using Google.
Use following keyword with Google and you will understand. I am in Love with Google really.
Here filetype : determines the type of file extension you want to search.
inurl : is used to look if the name is present in the url address.
Be aware of storing password in text files.