[khedoros]

It looks like there would be shared "runtime" packages, in specific versions, installed as part of the flatpak system (that is, not included in the app bundles themselves). Different runtimes could be installed, specific versions would be supported, etc.

The app itself would include any libraries/prerequisites outside of whatever flatpak defines as a "runtime library".

At least, that's my reading of how Flatpak works. I could be wrong on some of those points.