.OPUS File

The opus file extension is most likely best known for its use for OPUS audio format.

Opus is lossy audio compression file format encoded by IETF (Internet Engineering Task Force) audio codec and stored in OGG container. It is used by real-time interactive applications on the Internet (VoIP, Streaming, web frameworks).

MIME types:
audio/opus
audio/ogg

Files with opus file extension can be usually find as audio files in Opus audio file format from various Internet by VoIP services, streaming services, web frameworks etc.

How to open:

Your best option to playback *.opus files would be to use the free VLC player that has great format support.

How to convert:

OPUS audio can be converted to a wide range of other audio formats.