Fixed #18493 - Added instructions to locate the Django source files to the t

``/home/my_username/mytemplates/admin/base_site.html``. Don't forget that

``admin`` subdirectory.

.. admonition:: Where are the Django source files?

    If you have difficulty finding where the Django source files are located

    on your system, run the following command:

    .. code-block:: bash

        python -c "

        import sys

        sys.path = sys.path[1:]

        import django

        print(django.__path__)"

Then, just edit the file and replace the generic Django text with your own

site's name as you see fit.