C14: "keyed off"?

Name: Makoto Ueki
Email: makoto.ueki@gmail.com
Affiliation: Infoaxia, Inc. / WAIC
Document: TD
Item Number: C14
Part of Item: User Agent Notes
Comment Type: general comment
Summary of Issue: C14: "keyed off"?
Comment (Including rationale for any proposed change):
"User Agent and Assistive Technology Support Notes" reads "Internet Explorer 7 only changes the text size when the CSS is defined in a style element, keyed off an element as in the examples."

Q1. What does "keyed off" mean?
Q2. Where are the "examples"?

Proposed Change:
Need clarification for translation.