Awhile back MarcusAseth posted this picture

In it he asked about the blue box and arrow.  I too was stumped by it, and no one came back to answer.  Original Post: 

Turns out the blue arrow is when you have the source code in the parent directory to the project file.  I guess it was to tell a developer the file is located higher in the directory structure then the project file.

Hopefully anyone looking for an answer on this will find it.