Password prompt.
For me, that file was ratsnest.7z .
The archive opened. What I found was not pornography, not source code, not pirated movies. It was something far stranger. ratsnest.7z
Every so often, while digging through the dusty bins of a failing external hard drive or an abandoned NAS, you find a file that stops you cold. Password prompt
I right-clicked. 7-Zip -> Open Archive.