In TeXForm#
TeXForm parses this entry as a character leaf mapped to U+005B (LEFT SQUARE BRACKET).
\bbalpha\bbbeta\bbchi\bbdelta\bbDelta\bbdotlessi\bbdotlessj\bbepsilon\bbeta\bbgamma\bbGamma\txtbbLbrack
The [ symbol (Left square bracket, U+005B), written as \txtbbLbrack in LaTeX text mode.
TeXForm parses this entry as a character leaf mapped to U+005B (LEFT SQUARE BRACKET).
\bbalpha\bbbeta\bbchi\bbdelta\bbDelta\bbdotlessi\bbdotlessj\bbepsilon\bbeta\bbgamma\bbGamma\txtbbLbrack