Is there a browser plugin or method to find which php template an item is coming from?
the method I've been using is to find the item - such as a page title or whatever by using firebug extension for firefox. This will usually result in finding the related css class or id name for that item/element.
Then in dreamweaver I use the search function to find that class name from all of the files in the wordpress wp-content folder. Not sure of other programs like dreamweaver that have this search function but surely they exist.
I just wish there was a browser add on that would do for the php files what firebug does for css & html
The Query Monitor plugin is a very powerful tool for doing this. It shows the template and the queries and hooks the page generates; plus their load order, priority and whether it's core, parent theme, child theme or plugin. Very handle to have in your toolbox!
In WP Cli:
wp plugin install query-monitor --activate
On the repo: http://wordpress.org/plugins/query-monitor/