JPL's DE405 Ephemerides and the International Celestial Reference Frame
The ICRF was adopted by the International Astronomical Union as the fundamental celestial reference frame, replacing the FK5 optical frame as of 1 January 1998. It is specified by JPL as the reference frame for their DE405 ephemerides. However, they refer to a 1992 publication "Explanatory Supplement to the Astronomical Almanac" for a description of the required Chebychev polynomial expansions, which were originally used within the FK5 reference frame.
I'm not confused. I'm just showing off cause I have nothing else to do.