How to remove the "Save" button from checkout cart summary form?
One way of doing this is implementing hook_form_alter and hiding save button. Check example below:

function [MODULE_NAME]_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if ($form_id = 'YOUR_FORM_ID') {
    // Set access to FALSE will prevent rendering form element on form.
    // Check the hierarchy of 'Save' button, before using #access.
    $form['actions']['save']['#access'] = FALSE;
  }
}