Hello Dave–thanks for getting in touch!
The template used for the results should match the default view you have selected in Events > Settings > Display. Given that you mentioned events-gridview is referenced, I’d imagine that the Month View template is your default.
You can either check out the default template, which is located at /plugins/the-events-calendar/views/default-template.php. Or, you can dig deeper into the specific template for Month View at /views/month.php as well as the modules for it located in the /views/month subdirectory.
Does this help you locate the template you’re looking for? Please let me know. 🙂
Cheers!
Geoff