Marcel Taeumel uploaded a new version of Collections to project The Trunk:
http://source.squeak.org/trunk/Collections-mt.854.mcz

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

Name: Collections-mt.854
Author: mt
Time: 17 September 2019, 4:18:47.166388 pm
UUID: 2872f979-2300-5c47-ae2a-915321068785
Ancestors: Collections-mt.853

Fixes regression with Monticello configuration file-outs (.mcm).

I find it kind of surprising that #printElementsOn: is used as a serialization format ... ;-)

=============== Diff against Collections-mt.853 ===============

Item was changed:
  ----- Method: Collection>>printElementsOn: (in category 'printing') -----
  printElementsOn: aStream
  
+ 	aStream nextPut: $(.
+ 	
  	self
  		printElementsOn: aStream
+ 		separatedBy: String space.
+ 		
+ 	aStream nextPut: $).!
- 		separatedBy: String space.!

Item was changed:
  ----- Method: Collection>>printOn: (in category 'printing') -----
  printOn: aStream 
  	"Append a sequence of characters that identify the receiver to aStream."
  
  	self printNameOn: aStream.
+ 	self printElementsOn: aStream!
- 
- 	aStream nextPut: $(.
- 	self printElementsOn: aStream.
- 	aStream nextPut: $).
- !