[resolved] module html.tpl.php seems to be trumping theme version

we are developing a from-scratch theme in D7.
The designer has included the tag <meta content="width=device-width, initial-scale=1" name="viewport"> in the head section, and I placed this in the html.tpl.php file in our theme directory and cleared caches.

however, we are also using the HTML5 Tools module, and the theme debug output shows:

<!-- BEGIN OUTPUT from 'sites/all/modules/html5_tools/html.tpl.php' -->
<!doctype html>
<html lang="en" dir="ltr">
  <meta charset="utf-8" />

What’s the best way of getting this to work?

Well duh, it helps if the template is named html.tpl.php and not html.php.tpl
*going to hide under a rock for a while*

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/3/feed