How do AppImage tools decide what .so files to include? Why produced different .so-files-including list from different distros?

Compiled a Qt project and created .AppImage for it, on two different Linux distros ( Qt was installed via different ways). The two output .AppImage contain different .so files. Both .AppImage run. I want to know : 1. How do AppImage tools decide what libraries to include? 2. Why two .AppImage files have different libraries included, while they both run? Does one of them (or do both of them) have no 100% feature? Do they have different compatibility to various Linux distros? I used linuxdeploy + linuxdeploy-plugin-qt like this:

./linuxdeploy --plugin qt --appdir ........

Comparison of the two .AppImage's .so files: