Help Finding a BLP File from the UI

[Dekel]

I'm trying to find the BLP file for the red question mark icon on the microbar that has the character panel, mounts, dungeon journal, etc. With icons for spells and such I used the console and exported all of the art to my WoW folder but I can't find the microbuttons in there. I'm trying to find the art for the red question mark. I included an imgur link to help make what I'm asking for clear here:

http://imgur.com/a/RCQeH

Thanks in advance.