Xcode 2.4.1 had an excellent document "Xcode 2.4.1 Build Settings Notes" that listed and gave in-depth descriptions of Xcode build settings. This document could be brought up from the Help->Show Build Settings Notes menu item. Xcode 3 does have a build settings reference at http://developer.apple.com/documentation/developertools/Reference/XcodeBuildSettingRef/build_setting_ref/build_setting_ref but the explanations of the build settings are less comprehensive, and it's missing many of the build settings that are listed in the old document. Also, http://developer.apple.com/documentation/DeveloperTools/Conceptual/XcodeUserGuide/Contents/Resources/en.lproj/05_04_bs_build_settings/chapter_33_section_3.html#//apple_ref/doc/uid/TP40002691-SW6 says, "Note: Not all build settings support per-architecture definitions. The best way to find out whether a build setting supports per-architecture definitions is to use the build settings editor." No, this is in fact a very bad way to find out. Give us list. 28-Oct-2008: Engineering has reported that this documentation has been updated and released for your viewing. Please verify with the latest release of this documentation, and update this report with your results. 29-Oct-2008 Jeff Johnson: I need more information, please. This bug was cloned to rdar://problem/6036760 to track the two issues separately, although for me the titles are the same, so it's unclear which bug is tracking which issue. Which part(s) of the bug am I supposed to be verifying at the moment? Also, could you provide a link to the document(s)? The pages I linked to in the bug are now 404's. I do see http://developer.apple.com/documentation/developertools/Reference/XcodeBuildSettingRef/Build_Setting_Reference/build_setting_ref.html#//apple_ref/doc/uid/TP40003931-CH3-SW105 which has been updated recently. However, my first question when comparing that with the Xcode 2.4.1 Build Setting Notes is, where is the first item, NATIVE_ARCH_ACTUAL? Is this and related variants (NATIVE_ARCH_32_BIT) still supported?