is
   "false". Within base, it always leaves both attributes unchanged.

   The mover element [...] always sets displaystyle to "false" within
   overscript, but increments scriptlevel by 1 only when accent is "false".
   Within base, it always leaves both attributes unchanged.

   The munderover [..] always sets displaystyle to "false" within underscript
   and overscript, but increments scriptlevel by 1 only when accentunder or
   accent, respectively, are "false". Within base, it always leaves both
   at