As far as I can tell that's just where the three walls meet. Not load bearing because all that's above it is the roof, which I have to assume has rafters that run from ridge to the exterior wall. I guess I could be wrong, but it looks like just part of those non-load bearing walls. I have no idea what that is popping through the roof, but it looks like a leak waiting to happen.
[COLOR="DarkRed"][B]~ ToolGuy ~[/B][/COLOR]
[I]Save money on tools at [URL="http://mytoolbox.net"]MyToolbox.net[/URL]