The UX when reading large objects in the firestore explorer UI requires too much scrolling in small windows to find the information you are after. I'd propose to:

Note: "window" here refers to where the container where the data of a document can be found or alternatively where all the collection can be found. So the firestore explorer contains usually, a collection window, a document window, (a sub collections window, a document window,...).

• collapse maps by default, or collapse maps if the object is larger than the current window. When dealing with large objects it's currently annoying to find the information by scrolling.
• make the explorer bigger or add a button to have the explorer as full screen. Currently takes only half the space available on a 15 inch screen.
  • when you have a subcollection and you are watching a document in this sub collection, the collections and documents are aligned vertically. It would be nice to have a handle to be able to resize which of the sub collection or document take more vertical space.