In TeXForm#
TeXForm parses this entry as a character leaf mapped to U+21D0 (LEFTWARDS DOUBLE ARROW).
\to\rightarrow\longrightarrow\mapsto\xrightarrow\Rightarrow\Leftrightarrow\leftarrow\longmapsto\hookrightarrow\Longrightarrow\Leftarrow
\LeftarrowSymbol
The ⇐ symbol (Leftwards double arrow, U+21D0), written as \Leftarrow in LaTeX math mode.