I'm trying to learn how to manipulate display templates on SharePoint. I have a SharePoint online account but I can only see the .js files and not the HTML files we're suppose to work with.
Is this normal for SPO?
You need to turn on Publishing Features on your site for the HTML pages to show up, from there you can edit the HMTL files and create new display templates. And yes, this is documented no where.
Also, make sure you search at the right place for the HTML files:
All Files -> _catalogs -> masterpage -> Display Templates