In TeXForm#
TeXForm parses this entry as a character leaf mapped to U+21A6 (RIGHTWARDS ARROW FROM BAR).
\to\rightarrow\longrightarrow\mapsto\xrightarrow\Rightarrow\Leftrightarrow\leftarrow\longmapsto\hookrightarrow\Longrightarrow\implies
\mapstoSymbol
The ↦ symbol (Rightwards arrow from bar, U+21A6), written as \mapsto in LaTeX math mode.