If you hang out on bitcointalk as long as others here have, you see people like yourself who "found" such garbage on the internet (usually pay for it) then end up creating a topic like yours. Although most of them don't say where they found it, they usually say it is "their own wallet"!

These files are manually changed to look like they contain such large amounts. They rely on you to be greedy so that they can scam you, one way or another.
Usually they scam you by selling the file to you for small amount of money. Sometimes it is just a malicious file that would infect your system and steal your actual bitcoins. Sometimes the file is free but they rely on convincing you to pay a service they run to "recover" those coins