All configurations remain valid. Only lina has been tested. The kernel contains all the CORE words, plus some words essential for a self contained system, and some words making it a practical system. And yes it contains blocks, don't laugh, see below. It is still based on a single assembler source, where each word is preceeded by a m4 macro.
All configurations share a single master source file.
The GPL is relaxed to accomodate John Wavrik c.s. You can download the generic system with all the sources and documentation and tools to generate the different versions via ciforth.html. They, in combination with general information, are used to generate an exactly fitting manual. It is also easier to get it relevant and correct. Furthermore the GNU-c compiler info contains configuration information, like in Linux, you can retrieve information about how to build 68K embedded systems.