ownCloud gives you freedom and control over your own data. A personal cloud which runs on your own server.
Quality:
Depencencies:
https://doc.owncloud.org/server/8.2/developer_manual/app/index.html
https://owncloud.org/contribute/
Please submit translations via Transifex: https://www.transifex.com/projects/p/owncloud/
For more detailed information about translations: http://doc.owncloud.org/server/8.2/developer_manual/core/translation.html