[syslog-ng] pattern documentation for patterndb

I am sure I have asked this question before but I can’t find the answer now. The Admin Guide has a very sort section on patterns with a couple of examples. I can’t find the detailed docs for the actual pattern elements (parser types). I seem to remember that these we documented in a separate pdf but I can’t find it. I add new rules about once a year and struggle with it every time! Russell