Not sure of the proper place to report this, and subversion.apache.org doesn't say (which is in itself a bug, though one that's likely to get fixed soon), so I'm posting here (in case it helps for anyone to know), and I'll post separately to Apache's infrastructure list.
In Firefox 3.5.6, I visited http://mail-archives.apache.org/mod_mbox/subversion-dev/201001.mbox/browser and clicked on one of the messages (let's pick one at random): http://mail-archives.apache.org/mod_mbox/subversion-dev/201001.mbox/ajax/%3c4b42936d.10...@mark.mielke.cc%3e (That's one of Mark Mielke's messages in the "Re: Subversion in 2010" thread.) The message is displayed in a horribly broken way in the browser. At the top, the browser shows a warning bar that says "This XML file does not appear to have any style information associated with it. The document tree is shown below.". Below that, it... shows the document tree, complete with angle brackets and attributes and everything. The body of the message is visible, sort of, but this is surely not the intended UI :-). Not sure if this is true for all Apache lists or just Subversion's. -Karl