\k in inline math

[Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk>]

\starttext
$\k T$
\stoptext

The above test file, to my surprise, compiled fine.  [In Plain TeX I
usually define \k as \kappa, but I had forgotten to carry over that
definition.]  The pdf output showed a T with little hook as a subscript.

I can redefine \k as \kappa, but that might overwrite an important
definition.  However, I can't figure out where \k is defined.  With
\tracingmacros=1, the log had:

  \k ->\dohandleaccent {k}

but lots of grepping in the context sources only produced:

texmf/tex/context/base/mult-ini.tex:71:\def\k!prefix!{k!} \def\l!prefix!{l!} \def\m!prefix!{m!}

-Sanjoy

`A society of sheep must in time beget a government of wolves.'
   - Bertrand de Jouvenal