TYPO3 Core

If fetchExtension in typo3/sysext/extensionmanager/Classes/Utility/Connection notices that the md5 sums mismatch, it will call

throw new ExtensionManagerException('Error: MD5 hash of downloaded file not as expected:<br />' . $md5 . ' != ' . $expectedMd5, 1334426098);

This is catched in installFromTer as

catch (\TYPO3\CMS\Extensionmanager\Exception\ExtensionManagerException $e) {
            $errorMessages = array(
                $extension->getExtensionKey() => array(
                    'code' => $e->getCode(),
                    'message' => $e->getMessage(),
                ),
            );
        }

Which is coming from

    public function installFromTerAction(\TYPO3\CMS\Extensionmanager\Domain\Model\Extension $extension, $downloadPath) {
        list($result, $errorMessages) = $this->installFromTer($extension, $downloadPath);
        $this->view
            ->assign('result', $result)
            ->assign('extension', $extension)
            ->assign('unresolvedDependencies', $errorMessages);
    }

This will result in a typo3/sysext/extbase/Classes/Mvc/View/NotFoundView.php showing the following text:

Sorry, the requested view was not found.

The technical reason is: Array.

but should instead show a view relating to the extension manager.