Wright is a Mathematica package that implements the Wright omega function, a function related to the Lambert W function.
Download the paclet from the releases page, and install it by evaluating the following in Mathematica:
Needs["PacletManager`"]
PacletInstall["/path/to/paclet/Wright-1.0.paclet"]
where "/path/to/paclet/Wright-1.0.paclet" should be replaced with the actual path to the downloaded paclet file.
See the file Wright.nb for more detailed information on the package.