Why flatpak copies files to /run/user/1000/doc/

[RT123]

I installed keepassxc via flatpak and noticed that it copied my passwords database from folder that it was before
/home/user/data/password/pass.kdbx
to
/run/user/1000/doc/ee3a8011/pass.kdbx

I also noticed there are some files like jpg that I downloaded from internet via Firefox.

Is it normal? Is it safe that keepassxc puts database there?
Are these folders in this location temporary?

[Erick555]

Those files aren’t copied but mounted in virtual filesystem - they’re same files available under different path in order to be accessible for flatpak apps.