I received my receipt Notice of Action yesterday. At the bottom left corner, there's another LIN # listed. I am curious what it is about. Anybody?

I have that number too. It is something like LIN$00111XXXX. I guess that is their Internal accounting or control number.
We do not have to worry about that number at all. The application number LIN*0011xxxxx should be the only one we need to know and follow.