$ latex \\show\\textsuperscript
This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)
restricted \write18 enabled.
entering extended mode
LaTeX2e <2011/06/27>
Babel <3.9h> and hyphenation patterns for 54 languages loaded.
> \textsuperscript=macro:
->\protect \textsuperscript .
<*> \show\textsuperscript
?