List of source templates in sources

Does RM10 have an option to list templates that are being used in sources, and where?

Background:
In earlier years and RM versions, I happily used the inbuilt source templates, and at the time did not bother to edit them for footnotes and bibliography, as this was not important then.

Also, I found the many template variants confusing because of the slightly different template elements for a given source type, e.g. books.

I then began developing custom templates which I now use mostly.

Therefore, with hundreds of sources today I’d like to approach the footnote/bibliography editor more systematically. How do I find out what templates have been used and, if possible, where?

And a related question:
If I want to change a template in a source from in-built to custom, is this possible, and if so, how?

The source template being used for a source cannot be replaced by a different one.

There isn’t a list of what sources are using which source templates. You would need to manually make such a list.