If you activate developer mode in your settings, you can go to "Technical" > "Models". Here you can select the model you need, which in your case is res.company. Here you see an overview of all field that are used by this model. Please note that it also displays all fields from inherited models, denoted by the "In Apps" field. Alternatively, if you want to know the technical details, you could also inspect the source code on the github repository.

I hope this helps