I'm impressed that we try to save the user doing dumb things but OK if we protect the Json we also should protect the index.php, beside that you already said that the language file mentions the wrong filename. Should be an easy fix.

Someone has already changed the language file now to correct it. #31939

The problem would be that if you prevent someone deleting the file you also prevent them renaming the file so that they can create a completely new index.php perhaps for a new template design

You don't rename index.php, you copy it to create a new file.

A site with no active template index.php will be down, and in be in error.

A site with no active template index.php will be down, and in be in error.

Only if its the template in use

Oops. This was a bug in my previous commit. Should be fixed with 97a8329

Confirmed fixed

And to be clear @brianteeman I was not asking for a new feature, I was reporting that an existing feature was no longer working and was broken.

The code was already there

	if (base64_decode(urldecode($file)) == '/index.php')
		{
			$this->setMessage(Text::_('COM_TEMPLATES_ERROR_INDEX_DELETE'), 'warning');
			$url = 'index.php?option=com_templates&view=template&id=' . $id . '&file=' . $file;
			$this->setRedirect(Route::_($url, false));
		}

The feature to prevent index.php being deleted was added in 2013 - gulp

03-Oct-2013 Michael Babker
  + [#31266] GSoC 2013 - Improved Template Manager.  Thanks Ram Tripathi