I'm really not sure what component this bug applies to (if it applies to any at all), but… The "Thank you for testing WebKit!" page at http://nightly.webkit.org/start/ says: A new nightly build of WebKit is available! Please take a moment to update *to* it before continuing your testing. I've added asterisks around the spurious "to" in "update to it". The "Thank you for testing WebKit!" page should probably say: A new nightly build of WebKit is available! Please take a moment to update it before continuing your testing.
This text tells one to update *to* a new nightly build of WebKit, not to update a new nightly build. In other words, it looks correct to me.
You're absolutely right. I was reading it wrong. For what it's worth, "take a moment to update to it" still seems awkward to me; maybe "take a moment to install it" would be better, but that's probably just a personal preference.