Shelter App in FDroid, anyone using it?

[EndRacism]

I downloaded the Shelter App through fdroid to sand box faceboox. Is there anyone here using it who can explain how it works.

It appears most of my phone Apps are listed in under MAIN, then there are a few minor Apps place under a list called Shelter.

I don't know if apps in Main or Shelter are sand boxed. There just isn't any instructions anywhere. What does Clone do?