XAR (Executable Archive)

XAR (eXecutable ARchive), or XARs, is a self-contained executable/archive file format developed by Facebook.

A XAR file can contain a program (e.g. a Python script), along with that program's dependencies, and any other required data. When executed, it mounts a Squashfs filesystem.

Identification
A XAR file apparently begins with ASCII " " (see shebang), or something similar.

Links

 * https://github.com/facebookincubator/xar/