[section {[docidx] notation of keyword indices}] The docidx format for keyword indices, also called the [term {docidx markup language}], is too large to be covered in single section. The interested reader should start with the document [list_begin enum] [enum] [manpage {docidx language introduction}] [list_end] and then proceed from there to the formal specifications, i.e. the documents [list_begin enum] [enum] [manpage {docidx language syntax}] and [enum] [manpage {docidx language command reference}]. [list_end] to get a thorough understanding of the language.