A lot of what makes Tinycore what it is is done through scripts written in Ash. That is interpreted, not compiled.
There are no manuals documenting code. You have to be able to read and understand the code, and if you are lucky, there will be the occasional comment mixed in with the code.
The meat of the boot process of Tinycore seems to be in /etc/init.d/tc-config which, in addition to getting the system up and running, is a treasure trove of interesting scripting techniques - I've borrowed the command line parsing bit for other projects several times over the years - though I'm -still- a little hazy about some of the finer points of the syntax in that section.
However, even though I have a certain comfort level with -what- the script does, I've found that the details of -how- are sometimes obscure and I've often thought it would be really nice to have a thoroughly annotated (commented) copy of it for reference - not necessarily in the initrd, but perhaps in the wiki.