Different bookmark folder/categories in /e/OS browser - can someone explain?

Hello together,
in /e/OS browser I see several bookmark folder/categories:

  • Mobile bookmarks
  • bookmark toolbar (“Lesezeichenleiste”)
  • Tabs Collection
  • more bookmarks

What are the differences?

And if I store an URL into a bookmark, I cannot choose the folder/category - why? It seems to be a random procedure…

I don’t understand these different categories - can someone explain me that? Many thanks!