TYPO3 Core

It seems that the dependency checks currently only core packages.

The reason for this seems to be the naming of the requirements in the ext_emconf.php files. Since there only the extension names are required they are not considered as valid package keys in \TYPO3\Flow\Package\Package->getPackageMetaData().

If this check is disabled the dependencies will be considered but when an Extension has a dependency for a system extension \TYPO3\CMS\Core\Package\PackageManager->buildDependencyGraphForPackages() will throw an Exceptions because it only knows about non-system Extensions and it will also fail on requirements for php or typo3.

Extension loading order is important because Extensions might manipulate the configuration of other Extensions and therefore need to be loaded after them.