This sounds like you're looking to create some buzz around a mysterious file or a digital art project. Since "atowncalledsydney.rar" has a very "lost media" or "ARG" (Alternate Reality Game) vibe, here are a few ways to frame the post depending on where you're sharing it.

Found this on an old drive from 2009. Does anyone remember "atowncalledsydney.rar"?

The sky in these photos isn't the right color for Australia. Has anyone else seen the 'Blue Room' files in the subfolder? I think I found something I wasn't supposed to."

If you can, attach a glitchy, low-res image of a Sydney landmark or a screenshot of the file explorer showing the .rar icon.