Steps to reproduce the issue

Download an atom link from a Joomla 3.8.0 website.

Expected result

An "application/atom+xml" document

Actual result

Error 500 with text "class Joomla\CMS\Document\Renderer\Feed\JText not found".

System information (as much as possible)

Joomla 3.8.0, Purity III v 1.20, T3 v 2.6.7, running on Centos 7.4, Apache 2.4.8, PHP 7.1.9.

Additional comments

I think I found a little mistake in the file libraries/src/Document/Renderer/Feed/AtomRenderer.php. After comparing this file to RssRenderer.php in the same directory, I changed "JText" to "\JText" on lines 68 and 72. This made the atom feeds work for me.

Please review this. I'm not a PHP developer.