Question about flatpak-related user folders

[Solved, see explanation by @Neptr@lemmy.blahaj.zone below.]

I have the same version of Ubuntu (really Kubuntu) installed on two laptops, and also the same programs (debs, flatpaks, some snap) on both; they are almost mirrors.

Today I noticed that the .local/share/flatpak/ directory in one laptop has the following subfolders:

• db
• repo

while the homologous directory in the other laptop has these:

• db
• repo
• appstream
• app
• runtime
• exports

I'm just curious: does anyone know what the extra directories in the second laptop are about? The only difference in the flatpaks between the two laptops is with the GPUs: the first has Nvidia, Mesa, Intel; the second only Mesa and Intel (so I would be expecting more directories in the first than in the second, if any...).

Cheers!