Hi, I came to know this format just yesterday. I was trying to install some particular APK and I tried to backup and restore with titanium backup but it was force closing then I went to root folder there it has multiple split apk’s.
I tried to copy folder containing all files and re-copied after installing base APK but still it’s force closing but today I came across app called app cloner it is identifying app bundle and it can successfully restore it too but the catch is when I restore it installs app but it changes its package name. I’m working on it to find work around. Meanwhile you can try App Cloner.
This tutorial is more than six months old so questions are no longer supported at the moment for it. Thank you!