How would I add external content to a page?

I notice there are two embed/inject content style plugins but neither does what I want. I'd like to display the output from a script on the site on the home page. The script is not PHP and I do not want to use an iframe. Is there a way to do this?

I'm getting hit hard by the learning curves here, but making good progress! Thanks for any ideas.

Or maybe there's a way to use something like json and mustache? I'm totally unfamiliar with twig (for now), but maybe twig could take json and output it via a template?

Twig itself cannot, but a simple plugin could use a PHP-library or function to read the external data (for example in JSON-format), store it in the Data-folder, and output it it in a twig-template. You basically just need a plugin to read and save the data so it is available to you for manipulation.

Your plugin could also make an API call or you could sidestep the plugin altogether and use AJAX. See plugin cookbook

Thanks for the info.