On http://confluence.atlassian.com/pages/diffpages.action?pageId=116693&originalId=149078 if you select "show comment" under the version on the right, it shows the comment as: "Comment: $page.renderedVersionComment"

Also, http://confluence.atlassian.com/pages/pageinfo.action?pageId=116693 shows all the comments as $page.renderedVersionComment

I have not tested it locally yet so I am not sure if a stack trace is produced.