What is .flv file and how to open it?

An FLV file is a flash-compatible video file exported by the Flash Video Exporter plug-in (included with Adobe Animate) or other program with FLV file support. It consists of a short header, interleaved audio, video, and metadata packets. The file stores audio and video data in a similar format used by standard Flash (.SWF) files.

How to open .flv file?