What do the different icons beside Xcode projects mean?

Question

When I open Xcode, it prompts me to open recent projects. In the screenshot below, the second and third projects are the same, and the first is different.

What I Want To Know:

1) What is the difference between the white and blue Xcode icons at the left?

2) Given the the second and third projects are the same, one has a white icon and the other has a blue icon. What does it mean for them both to be listed?

Answer 1

The white icons are Xcode workspaces (.xcworkspace) and the blue icons are Xcode projects (.xcodeproj). A workspace can refer to one or more projects.

Here are examples of three different Xcode document types from my Open Recents menu: