In TeXForm#
TeXForm parses this entry as a character leaf mapped to U+2289 (NEITHER A SUPERSET OF NOR EQUAL TO).
The ⊉ symbol (Neither a superset of nor equal to, U+2289), written as \nsupseteq in LaTeX math mode.
TeXForm parses this entry as a character leaf mapped to U+2289 (NEITHER A SUPERSET OF NOR EQUAL TO).