How do I determine what the module is (or modules are) on a page? I apologize if there is a way that is obvious, but I cannot find it if it exists.

Please understand that I might be using the wrong terminology. I am asking as a non-developer; I am not sure what you mean by "tabmodule collection" but that sounds like programmer terminology. I am a programmer but I have not yet begun doing DNN module development and for this I am asking as a non-developer.

So let us say I am in the DNN home page. I have added a HTML module to it but I cannot find anything stating explicitly that there is a HTML module in the page. If I edit the page then I can edit the contents of the module and figure out that it is a HTML module but that is not a reliable way to do it and will not work in other circumstances.

You can go to "admin" --> "page management" and click on the page in question. Scroll down to the "modules" section and it'll show a list of all modules on that page. You can also delete any of the modules if needed.

Mark