When downloading a snapshot of Qt, the Binaries section lists both Mac OS X, and Mac OS X Debug Libs. The Debug Libs package however does not include any of the required binaries and tools (eg qmake), but the message shown by the installer is the same as that for the non-debug version (Welcome.rtf).
This is confusing, as one might install Qt and decide to use the debug libraries for development, but then ends up missing the tools.
1) make the debug lib package include also the binaries and tools (ie it should be usable by itself), or
2) point out that the debug libs has a dependency on the normal package, and that it should be installed first (perhaps with a check, but at least by modifying the Welcome.rtf file in the debug libs package)
(I put this under website since it could be pointed out there already, could be an installer suggestion too on OS X)