In TeXForm#
TeXForm parses this entry as a character leaf mapped to U+039B (GREEK CAPITAL LETTER LAMDA).
\bbalpha\bbbeta\bbchi\bbdelta\bbDelta\bbdotlessi\bbdotlessj\bbepsilon\bbeta\bbgamma\bbGamma\txtbfbbLambda
\txtbfbbLambdaSymbol
The Λ symbol (Greek capital letter lamda, U+039B), written as \txtbfbbLambda in LaTeX text mode.