Motherboard Tray
Having a motherboard tray (marked red) is very helpful if you change hardware a lot. The tray with the motherboard and the cards can be easily removed.
The tray is held in place by two thumbscrews. I had difficulties getting to the second screw (2nd and 3rd picture). In addition to that it was locked very tight from the factory and I ended up using a screwdriver to remove it. Maybe it's easier for people with asian-sized hands. When you put the tray back in and do not tighten the screw too much it's no problem getting it out again since you can touch the screw with your fingers. It's just hard to exercise a lot of force. The first screw was no problem to reach though.
Once the screws are gone you can slide the tray toward the front and then take it out of the case.
The tray is huge. Even the full-sized ABIT AA8XE looks small on it.