Canon no longer lists the YJ18x9B4 on its main consumer support page. Here is where the of the internet hides the PDF:

The is a cornerstone of the IFpro video lens series, specifically designed for 2/3-inch B4 mount cameras used in professional broadcast and ENG (Electronic News Gathering) environments.

This guide covers the top section, but for full specifications (back focus charts, lubrication points, and parts list), you need the official .