help what does that mean?

[abro]

Good morning thanks to those who help me
I found this small town in two views, it would seem like a mass center but it is also indicated in section , according to you what you want to indicate?

 

[Be_on_edge]

c.o.g. = center of gravity

I think it was put in the section because only side view in which to show it.

 

[abro]

I imagined but precisely I did not understand xché in view in section, so much to confuse me with a hole of plug.
thanks always super