Extend a Commerce (v2) order template in the control panel Is there a way to extend (extend, not replace) the default Commerce order templates in the control panel? 
I'd like to display important custom fields in a prominent way on the first tab. (and not tucked away on a second tab as is normal with custom fields)
I found the solution in another question:
Writing a plugin that triggers on a Control Panel Template Hook?

Based on this answer we can use:

Craft::$app-&gt;getView()-&gt;hook('cp.commerce.order.edit.main-pane', function(array &amp;$context) {
    return '&lt;a href="#" class="btn"&gt;My Button!&lt;/a&gt;';
});