The package loads the fixltx2e package from the LaTeX distribution,
and etex.sty from the e-TeX distribution.  The package then patches
the \- (discretionary hyphen command) to use the current hyphen
character (which may be different from than the default, which is the
character at the ASCII hyphen slot), and the \textsuperscript command
(from the LaTeX kernel) and the \textsubscript command (from the
fixltx2e package).  The package also provides parameterised versions
of the "bumpy road" logos for TeX, LaTeX and XeTeX; these versions of
the logos are designed to respond to the font that is being used for
typesetting.

Homepage:
https://ctan.org/pkg/xltxtra
