What do the “M” and “A” icons in the Project Navigator of Xcode 4 mean when I create a new project?

Question

Those characters refer to the source control.

? – Unversioned
M – Modified
A – Added
A+ – Moved / renamed
U – Newer version of a file on source control
I – Item is being ignored (e.g. with the svn:ignore property).
! – Item is missing (e.g. you moved or deleted it without using svn). This also indicates that a directory is incomplete (a checkout or update was interrupted).

Ref: http://svnbook.red-bean.com/en/1.2/svn.ref.svn.c.status.html