安装出现下面问题，是什么问题呢?

symfony/var-dumper suggests installing ext-symfony_debug ()
symfony/translation suggests installing symfony/config ()
symfony/security-core suggests installing symfony/expression-language (For using the expression voter)
symfony/security-core suggests installing symfony/validator (For using the user password constraint)
symfony/routing suggests installing doctrine/annotations (For using the annotation loader)
symfony/routing suggests installing symfony/config (For using the all-in-one router or any loader)
symfony/routing suggests installing symfony/expression-language (For using expression matching)
symfony/event-dispatcher suggests installing symfony/dependency-injection ()
symfony/http-kernel suggests installing symfony/browser-kit ()
symfony/http-kernel suggests installing symfony/class-loader ()
symfony/http-kernel suggests installing symfony/config ()
symfony/http-kernel suggests installing symfony/dependency-injection ()
psy/psysh suggests installing ext-pcntl (Enabling the PCNTL extension makes PsySH a lot happier :))
psy/psysh suggests installing ext-pdo-sqlite (The doc command requires SQLite to work.)
monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log messages to AWS services like DynamoDB)
monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server)
monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required))
monolog/monolog suggests installing graylog2/gelf-php (Allow sending log messages to a GrayLog2 server)
monolog/monolog suggests installing raven/raven (Allow sending log messages to a Sentry server)
monolog/monolog suggests installing rollbar/rollbar (Allow sending log messages to Rollbar)
monolog/monolog suggests installing ruflin/elastica (Allow sending log messages to an Elastic Search server)
monolog/monolog suggests installing videlalvaro/php-amqplib (Allow sending log messages to an AMQP server using php-amqplib)
league/flysystem suggests installing league/flysystem-aws-s3-v2 (Allows you to use S3 storage with AWS SDK v2)
league/flysystem suggests installing league/flysystem-aws-s3-v3 (Allows you to use S3 storage with AWS SDK v3)
league/flysystem suggests installing league/flysystem-azure (Allows you to use Windows Azure Blob storage)
league/flysystem suggests installing league/flysystem-cached-adapter (Flysystem adapter decorator for metadata caching)
league/flysystem suggests installing league/flysystem-copy (Allows you to use Copy.com storage)
league/flysystem suggests installing league/flysystem-dropbox (Allows you to use Dropbox storage)
league/flysystem suggests installing league/flysystem-eventable-filesystem (Allows you to use EventableFilesystem)
league/flysystem suggests installing league/flysystem-rackspace (Allows you to use Rackspace Cloud Files)
league/flysystem suggests installing league/flysystem-sftp (Allows you to use SFTP server storage via phpseclib)
league/flysystem suggests installing league/flysystem-webdav (Allows you to use WebDAV storage)
league/flysystem suggests installing league/flysystem-ziparchive (Allows you to use ZipArchive adapter)
league/flysystem suggests installing predis/predis (Allows you to use Predis for caching)
laravel/framework suggests installing aws/aws-sdk-php (Required to use the SQS queue driver (~2.4).)
laravel/framework suggests installing doctrine/dbal (Required to rename columns and drop SQLite columns (~2.4).)
laravel/framework suggests installing guzzlehttp/guzzle (Required to use the Mailgun and Mandrill mail drivers (~5.0).)
laravel/framework suggests installing iron-io/iron_mq (Required to use the iron queue driver (~1.5).)
laravel/framework suggests installing league/flysystem-aws-s3-v2 (Required to use the Flysystem S3 driver (~1.0).)
laravel/framework suggests installing league/flysystem-rackspace (Required to use the Flysystem Rackspace driver (~1.0).)
laravel/framework suggests installing pda/pheanstalk (Required to use the beanstalk queue driver (~3.0).)
laravel/framework suggests installing predis/predis (Required to use the redis cache and queue drivers (~1.0).)
phpdocumentor/reflection-docblock suggests installing dflydev/markdown (~1.0)
phpdocumentor/reflection-docblock suggests installing erusev/parsedown (~1.0)
phpspec/phpspec suggests installing phpspec/nyan-formatters (~1.0 – Adds Nyan formatters)
sebastian/global-state suggests installing ext-uopz (*)
phpunit/php-code-coverage suggests installing ext-xdebug (>=2.2.1)
phpunit/phpunit suggests installing phpunit/php-invoker (~1.1)
Generating autoload files
Generating optimized class loader
Compiling common classes
Application key [UAVg4vtkjtMbODIpx5XArk1D5INOp9Q3] set successfully.