I can prepare some documentation, there are 2 main topics.
1. symbols for silicon devices (nfet, pfet resistors and so on), the symbols have been drawn using the skywater-pdk docs
as a reference.
2. standard cell symbols, these are based on this document
Let me know what information you need i will do my best to provide it... in the mean time i will create a readme in each directory explaining what it is all about.