Network prefetch on or off in TorBrowser ?

Doing about:config shows that:

network.dns.disablePrefetch = true network.prefetch-next;true

On the one hand it looks as though it's disabled, on the other it's on. I don't know which value has more precidence in FF here.

Is this on or off ? It should be off, there should be no dns lookups or starting to download urls without user action.

Apologies if this has already been covered.

v. 3.6 (i think)

Trac:
Username: DrMikeTwiddle