title: PBXBuildFile vs PBXFileReference section
body: <p>What is the difference between PBXBuildFile and PBXFileReference in project.pbxproj? Does it matter if a file is listed in both of the sections? What is the policy what file in which section should get?</p>
  
  <pre><code>/* Begin PBXBuildFile section */
          3D081B83146ACE36000CC86B /* B767.png in Resources */ = {isa = PBXBuildFile; fileRef = 3D081B82146ACE36000CC86B /* B767.png */; };
  
  /* Begin PBXFileReference section */
          3D081B82146ACE36000CC86B /* B767.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = B767.png; sourceTree = "&lt;group&gt;"; };
  </code></pre>