Email templates may refer to the complete change log in an event notification. The variable is called: $!changeItems.
$!changeItems is a collection of Change Item objects with the attributes below:
Name of the field that was changed
String representation of the old value of the field or a comma-separated list of removed items in case of multi-value fields
String representation of the new value of the field or a comma-separated list of removed items in case of multi-value fields
Example template code to loop through the change items
#foreach($changeItem in $!changeItems)
Field name: $!changeItem.getString("field")
Old value: $!changeItem.getString("oldstring")
New value: $!changeItem.getString("newstring")
The same construct is used by the renderChanges macro.