Excluding pages in twentyten.

I’d like to exclude some pages from the horizontal bar at the top in the twentyten theme.

I’ve seen the WP Codex documentation for what to include in the unordered list in order to exclude pages. But, call me stupid, I can’t find which php file in the theme has this list. Once I find the list, I’m pretty confident in my ability to edit it. But I can’t find it.

So, where is the php file that has the wp_list_pages code?