This is a pre-compiled distribution of Coreboot with the aim of sticking as close to free as in freedom philosophy.

Most importantly it identifies devices, which can be booted with as little involvement of non-free blobs (binary large objects) and pre-configures coreboot to support exactly that use-case, whilst enabling features off by default in Coreboot like CMOS settings. Also it disables the Intel Management engine, not by patching it out, but by booting in a way which does not require it to load in the first place, if possible. Depending on architecture, like some laptops with Core2 and some server boards like any AMD processor from the Bulldozer era can be booted off-of firmware images, which contain no black-box blobs from the manufacturer or parts, which cannot be recreated from FOSS code. Most crucially, this also includes μCode updates.

So it could be seen as a tradeoff in stability and performance to get close to the ideal of extending FOSS into the realm of Hardware.