Just a quick note to Firefox nightly testers and bug triagers: I pushed
a patch that removed the old HTML fragement sink (which had had the comment
“XXX THIS IS TEMPORARY CODE” since May 1999). As a result, the
html5.parser.enable pref does not affect fragment parsing
(innerHTML or createContextualFragment) anymore.
Therefore, flipping the pref is no longer a valid way of checking if a
fragment parsing bug is a regression from the HTML5 parser. For the time
being, the pref still affects the parser choice for parsing HTML received
from the network, but eventually the pref is going to go away altogether.