The revision tag pops up onmouseover. It has some links in it; for example, in "The stable version was checked on 2011-02-10. There is 1 pending change awaiting review." there are links on "stable version", "checked" and "1 pending change".
When the mouse pointer is moved from the little revision tag box towards the popped up box, the box often disappears without giving the user a chance to ever click the link. It is not completely consistent - sometimes i am able to catch the link, sometimes not. More often than not it does happen.
I tried it in Chrome and Firefox on XP in he.wikisource and in pl.wikipedia (with interface language set to Polish and to English) - it happened all the time.