It's a rather convoluted one though: rather than telling libraries to install in different places, they're installed "globally" within a chroot, which then gets tarred-up, which then gets untarred, then bind-mounted, then chrooted-into again.
It's not "cross-platform" at all, since Docker builds on Linux containers. For example, the Docker applications for Windows and macOS just run a Linux VM behind the scenes.
AFAIK you can't run Windows binaries using Docker, even if you're using Windows, since it's running in a Linux VM; likewise for macOS binaries on macOS, Solaris on Solaris, etc.