Pasting Enter equals what?

When creating content using the Classic editor pressing a new line doesn’t create lots of unwanted vertical white space.
In Text mode it just moves it to the next line.
Just what we (think) we want.

Switching to Visual retains the breaks.

But the Enter key creates a new implied paragraph… with a one line break.

The difference between Classic Editor and Block can be summarised.
Classic Editor doesn’t show its working.
Block Editor does.

Here’s another one.
Sometimes we get two br’s
When we press Shift-Enter
Is this just in the first block?

Summary file