I see these 'Table' buttons:

I can rename them, but what purpose do they serve? In all the examples they are just called 'Table', why are they simply not the table name?
And what does the + do?
I see these 'Table' buttons:

I can rename them, but what purpose do they serve? In all the examples they are just called 'Table', why are they simply not the table name?
And what does the + do?