David T. Lewis uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-dtl.1162.mcz

==================== Summary ====================

Name: Kernel-dtl.1162
Author: dtl
Time: 17 March 2018, 3:11:04.807847 pm
UUID: 46f46dde-06c6-4189-a8e6-4a07eda959bf
Ancestors: Kernel-eem.1161

Use #rootClasses introduced in Environments-fbs.27

=============== Diff against Kernel-eem.1161 ===============

Item was changed:
  ----- Method: Class class>>rootsOfTheWorld (in category 'inquiries') -----
  rootsOfTheWorld
  	"return a collection of classes which have a nil superclass"
+ 	^Smalltalk globals rootClasses!
- 	^(Smalltalk globals select: [:each | each isBehavior and: [each superclass isNil]]) asOrderedCollection!