[Flow] Composer question regarding Flow

[Martin Kutschker]

Hi!

I'm new Flow and tried to fetch it via composer. So I created in an 
empty directory a simple composer.json:

{
         "require": {
                 "typo3/flow": "2.*",
         }
}

But I ended up with this:

Your requirements could not be resolved to an installable set of packages.

   Problem 1
     - typo3/flow 2.2.2 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.2.1 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.2.0 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.1.2 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.1.1 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.1.0 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.0.2 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.0.1 requires doctrine/migrations dev-master -> no 
matching package found.
     - typo3/flow 2.0.0 requires doctrine/migrations dev-master -> no 
matching package found.
     - Installation request for typo3/flow 2.* -> satisfiable by 
typo3/flow[2.0.0, 2.0.1, 2.0.2, 2.1.0, 2.1.1, 2.1.2, 2.2.0, 2.2.1, 2.2.2].

Only after I added mannually the dependcy to doctrine/migrations 
composer would fetch me all the packages.

{
         "require": {
                 "typo3/flow": "2.*",
                 "doctrine/migrations": "@dev"
         }
}

Is this normal and if so why?

Masi

PS:

Why are the Doctrine and Symfony packages fetched from packagist.org and 
is the Flow stuff cloned?