Full image builds show module name and version as 'name@version':
[3,640s][trace][gc,classhisto ] GC(1) 4: 5067 162144 java.lang.String (java.base@15-internal)

Exploded builds don't have a version and prints 'name@'
[4,361s][trace][gc,classhisto ] GC(1) 3: 7144 228608 java.lang.String (java.base@)

This looks weird and I propose that we drop the trailing @ when there's no version string:
[4,361s][trace][gc,classhisto ] GC(1) 3: 7144 228608 java.lang.String (java.base)