Strictly speaking, this is not a circuit. It looks similar to a block diagram but it's not of those either.
Block diagrams only indicate the flow of a signal, or the way blocks of circuits are linked. They don't give detail of the connections between components, or supply voltages, as circuits do.
The resistor blocks shown constitute an attenuator that reduces the level of the incoming signal coming from Address1, to a level suitable for FPGA. As such, the Resistor 1 block should be left out and Resistor 2 block should be renamed 'Attenuator'.
The only way a block would normally be shown in a circuit is when it is an IC where the internal components are complex and the block can be treated as a 'black box'. In that case, numbers attached to it are normally the pin numbers of the IC.
Think of it like a block diagram is a flow path that shows the key functions of a circuit at a glance, but a circuit shows all the connections and detail.