The Steam Link hardware is a single core ARMv7 processor using the hard-float ABI, running at 1 GHz, with neon instruction support. It has approximately 256 MB of available RAM and 500 MB of usable flash storage.
The Steam Link software is custom Linux firmware based on kernel 3.8 and glibc 2.19.
The Steam Link SDK has support for the following major APIs:
OpenGL ES 2.0
The SDL game controller API is recommended for Steam Controller support on the Steam Link.
examples - very simple example applications to demonstrate how to build applications using the SDK
external - source code to 3rd party components of the Steam Link, each directory has a "build_soc.sh" script to rebuild the component.