The name of the file remains the same unless you change it explicitly. I'm not sure why you'd want to change it every time... it just doesn't add any security benefit at all, meanwhile making it harder for you to select the correct file to decrypt and synchronize.
You can find out the type of file by running the file command on it. So even if it's completely randomized, in an attempt to "hide in plain sight", it's very easy to figure out which files are KeePass database files. What's important is that you use a strong password and optionally additional keys to protect it.