Hi Ko-hey,
the OBDS is a test suite for some (maybe all) i.MX boards (on-board diagnostic suite). It's used internally in NXP to bring up and test new development boards. In the i.MX28 times I know it was also intended to go out, to provide customers with a software which enables them to test their own i.MX based boards in an early project stage. For the i.MX6 I haven't seen packages like this going to the outside.
In my opinion, the SD card you got with this 6DL package is simply a mistake.
In the link from Joan Xie for the Linux software, you need to go to the "Board Support packages", click on "More" and then you can download the demo binaries of the latest release 4.1.15_2.0.0 (L4.1.15_2.0.0_MX6QDLSOLO, 2.2Gbytes). These demo binaries work for the Quad/Dual/Solo/DualLite.
Regards,
Bernhard.