Unable to decompress gzip file ("not in gzip format")

I've been tasked with diagnosing an issue with a webpage, and I've been able to trace the issue back to a gzip'ed JavaScript file, jquery.min.js.gz. To view the code, I've downloaded and attempted to unzip the file on my Linux machine. I'm met with a not in gzip format error. The file jquery.min.js.gz command returns that the file is "data", and head jquery.min.js.gz returns the attached (StackExchange seems forbids posting some of what appear to be Korean characters). Examining the file in Vim, it contains the sort of binary data I'd expect from a gzip file. What's going on here?