- AppImage: it packs Linux apps into a tar file so you can unzip it later and run the executable of the app. The main selling point of AppImage is it's distro-independent
- XAR: it packs dynamic languages programs (python, node.js, lua) into a executable file. The executable includes the language runtime, a fuse filesystem to mount the program's source code.
In conclusion, I don't think you ever needs to make an AppImage for XAR executable file.
Not exactly: An AppImage file packs a Linux app as a compressed ISO image with an ELF preamble that is able to access the contents of the ISO image without unpacking, so you can just double click the package and run the app without ever unpacking it.
Is there anything XAR can do that AppImage cannot?
There are very complex Python applications (e.g., Ultimaker Cura) which are packaged in the AppImage format as self-standing single-file executables, including the Python interpreter, libraries, and other resources.
- AppImage: it packs Linux apps into a tar file so you can unzip it later and run the executable of the app. The main selling point of AppImage is it's distro-independent
- XAR: it packs dynamic languages programs (python, node.js, lua) into a executable file. The executable includes the language runtime, a fuse filesystem to mount the program's source code.
In conclusion, I don't think you ever needs to make an AppImage for XAR executable file.