This article describes the different formats that use the EXO extension. It also explains how to open each format and how the conversion works.
A file with the EXO file extension is a video chunk file. These are literally pieces of a larger file that are created when an offline video is requested from a website or app that hosts video streams, such as within the YouTube app on some Android devices.
YouTube EXO files in particular are often encoded and compressed. Other files that come from online videos may also be encoded.
Some files with this extension may not be video files at all, but Motorola EXORmacs data files (part of the Motorola S-record format). Others may be generic system files that support certain proprietary software programs.