Q:

Does version 5.27 break links to live and test-drive pages for contribution pages? 

Just upgraded a WP site to Civi 5.27.1.  From 'Manage Contribution Pages' the links as given to Live and Test Drive for a given contribution page appear broken - i.e. they create a white screen indicative of a fatal error.  The URLs provided are:
Live Page: https://www.example.org/wp-admin/admin.php?civiwp=CiviCRM&q=civicrm%2Fcontribute%2Ftransact&reset=1&id=1
and
Test Drive: https://www.example.org/wp-admin/admin.php?civiwp=CiviCRM&q=civicrm%2Fcontribute%2Ftransact&reset=1&id=1&action=preview
If I edit these URLs to replace "civiwp" with "page" they work fine. 
Bug, or am I doing something wrong? 
Seems to be related to this announcement: https://civicrm.org/blog/kcristiano/civicrm-526-and-wordpress-important-notice
Update: nothing in the Civi log. 

A:

Enabling Cleaner URLs, as described here: https://docs.civicrm.org/sysadmin/en/latest/install/wordpress/#enabling-cleaner-urls-for-wordpress
appears to resolve this problem.