Updated: Comment #N
Problem
Something changed in the last 4 or 5 days. I did a git clone of D8 and a standard install. I use a Mac and normally run my dev installs in 'dirty url' mode'. No errors were presented. But the front page looked like Stark was the theme instead of Bartik. When I modified .htaccess to support clean url's then the exact same install front page displayed as expected. The error I see in Firefox's web console is:
Request URL: http://localhost/~rocks/drupal8/sites/default/files/css/css_cBlBJp_KYMhQgOj76WIX8Vqo0Mnzt4bv9RlJbgnChGY.css?0
Request Method: GET
Status Code: HTTP/1.1 404 Not Found
See attached images:
Clean URLs
Dirty URLs
getEntityTypeFromStaticClass(