Fwd: missing \usepackage{mhchem} in helpfile Math.lyx

[Wolfgang Engelmann]

In the helpfile Math.lyx it is stated:

To export this document to PDF, PS or DVI the LaTeX-packages braket, 
cancel, eurosym, mathdots, mathtools, mhchem, undertilde and was should 
be installed. If they are not installed the document can be exported 
anyway but the sections where the packages are required will not appear 
in the output. An exception is mhchem; if it is not installed, this file 
cannot be exported.

The latest PDF-version of this document can be found 
here:https://wiki.lyx.org/LyX/Manuals#Math

However, I could not find \usepackage{mhchem} in this helpfile Math.lyx
Is this intentional? Or included in another \usepackage?

Wolfgang