Is there a way to find a related list is coming from?

Is there a way to find a related list is coming from?

I'm working at  company and they had someone create a CRM but so many things are disconnected, so I'm building to connect and redo the CRM. However, I can't figure out where certain related lists are coming from. I would check a place to see if it has a lookup or multiselect lookup, and check their properties to see the name but the names wouldn't match. So is there a way to find where a related list is coming from?