Each bit position and value in rsync's output:

  YXcstpoguax  path/to/file
  |||||||||||
  ||||||||||╰- x: The extended attribute information changed
  |||||||||╰-- a: The ACL information changed
  ||||||||╰--- u: The u slot is reserved for future use
  |||||||╰---- g: Group is different
  ||||||╰----- o: Owner is different
  |||||╰------ p: Permission are different
  ||||╰------- t: Modification time is different
  |||╰-------- s: Size is different
  ||╰--------- c: Different checksum (for regular files), or
  ||              changed value (for symlinks, devices, and special files)
  ||
  |╰---------- the file type:
  |            f: for a file,
  |            d: for a directory,
  |            L: for a symlink,
  |            D: for a device,
  |            S: for a special file (e.g. named sockets and fifos)
  |
  ╰----------- the type of update being done::
               <: file is being transferred to the remote host (sent)
               >: file is being transferred to the local host (received)
               c: local change/creation for the item, such as:
                  - the creation of a directory
                  - the changing of a symlink,
                  - etc.
               h: the item is a hard link to another item (requires
                  --hard-links).
               .: the item is not being updated (though it might have
                  attributes that are being modified)
               *: means that the rest of the itemized-output area contains
                  a message (e.g. "deleting")

Some example output from rsync for various scenarios:

  >f+++++++++ some/dir/new-file.txt
  .f....og..x some/dir/existing-file-with-changed-owner-and-group.txt
  .f........x some/dir/existing-file-with-changed-unnamed-attribute.txt
  >f...p....x some/dir/existing-file-with-changed-permissions.txt
  >f..t..g..x some/dir/existing-file-with-changed-time-and-group.txt
  >f.s......x some/dir/existing-file-with-changed-size.txt
  >f.st.....x some/dir/existing-file-with-changed-size-and-time-stamp.txt
  cd+++++++++ some/dir/new-directory/
  .d....og... some/dir/existing-directory-with-changed-owner-and-group/
  .d..t...... some/dir/existing-directory-with-different-time-stamp/