NRV (Not Really Vanished)
From Just Solve the File Format Problem
NRV (Not Really Vanished) is a data compression library, and associated demonstration software. It was developed by Markus Oberhumer, as a possible successor to LZO. It apparently had a file format associated with it.
A subset of NRV is used in UPX's UCL compression.
Despite its name, the NRV software seems to have really vanished from the internet. The website[1] indicates it was discontinued in favor of LZO Professional[2].
Identification
According to IDArc, NRV (demo) files start with bytes 00 9e 6e 72 76 ff
.
Software
We haven't been able to find any NRV software. The demo software was in a file named nrvdemo1.zip.