Change record status: 
Project: 
Introduced in branch: 
8.x
Description: 

In Drupal 7, #type 'markup' was a distinction without a difference and caused confusion because including '#type' => 'markup' in a render array was always optional and did not affect the rendering of markup added using the #markup render array key in any way.

In Drupal 8, you can still add arbitrary markup to render arrays using the #markup render array key, but '#type' => 'markup' is no longer a valid type.

Unneeded #type specification:

array(
  '#type' => 'markup',
  '#markup' => 'Some arbitrary markup.',
);

Correct (for both Drupal 7 and Drupal 8):

array(
  '#markup' => 'Some arbitrary markup.',
);

In Drupal 7, drupal_render() set #type to markup internally before rendering if #markup was set but #type was not set. In Drupal 8, we no longer specify a #type at all for markup, since '#type' => 'markup' no longer affects the behaviour of the #markup render array key.

Impacts: 
Module developers
Themers
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done