Better error handling on dummy without permissions (instead of "RuntimeException" Fatal Error)
If you unpack the dummy package in a blank vhost, but the webserver has no permissions to create files (under typo3temp etc) you get a PHP "Fatal Error" like this:
Fatal error: Uncaught exception 'RuntimeException' with message 'Could not create directory "/.../typo3temp/Cache/Code/cache_core/"!' in /.../typo3_src/typo3/sysext/core/Classes/Cache/Backend/SimpleFileBackend.php on line 197
While this is all true, this is probably the first impression a newby user will get from TYPO3's "usability".
Better would be at this situation output a nice instruction page (or a link to a Wiki page) on how to proceed (i.e. how to change permissions, which directories needs to have "write permissions" etc..).