Missing .dts files in Debian distro?

Hi all, just a quick question. I’m new to programming embedded Linux, having done most of my work for various embedded applications using to-the-metal AVR programming (using home brew cyclic executives and the like, I’ve never really had the need for an actual OS until now) and doing VHDL design on FPGAs (and doing the associated PCB circuit design), however I am slowly wrapping my head around programming for something running an actual OS. I could toss this over to an actual software guy, but it seems like a good learning experience.

I foresee needing to design my own carrier board (essentially a large cape) and am trying to learn about device trees and device tree overlays. I noticed however, that the available device tree sources (and even the blobs) found on the latest official Angstrom and Debian distros are much different - with there seemingly being far fewer in the file system of the Debian distro. Am I just looking in the wrong place or were many of the sources just left out of the debian distro?

Thanks for the help.