With the release of Oracle VM VirtualBox 5.0, I've seen more customer interests in VirtualBox, which has become the de facto software development choice. I also received some questions about the software licensing and the extension pack.
The base package of VirtualBox, beginning with 4.0, consists of all open-source components and is licensed under the GNU General Public License V2.
Oracle provides the extension pack with the following added functionality such as the virtual USB 2.0 (EHCI) device, the virtual USB 3.0 (xHCI) device, VirtualBox Remote Desktop Protocol (VRDP) support, host webcam passthrough, Intel PXE boot ROM, experimental support for PCI passthrough on Linux hosts. The 5.0 release delivers encryption of disk images feature via the extension pack.
The extension pack is under the Personal Use and Evaluation License. So for corporate users, you can purchase commercial licenses from Oracle to access the above enterprise features and receive support to cover both the base and the extension pack.
To view the extension pack that is currently installed, please start the VirtualBox Manager (on any of the host OS). From the "File" menu, please select "Preferences". In the window that shows up, go to the "Extensions" category which shows you the extensions which are currently installed and allows you to remove a package or add a new one. See the screenshot below:
Alternatively you can use VBoxManage on the command line (on any of your host OS):
$ VBoxManage list extpacks Extension Packs: 1 Pack no. 0: Oracle VM VirtualBox Extension Pack Version: 5.0.0 Revision: 101573 Edition: Description: USB 2.0 and USB 3.0 Host Controller, Host Webcam, VirtualBox RDP, PXE ROM, Disk Encryption. VRDE Module: VBoxVRDP Usable: true Why unusable: