This installer runs a *.bat file that clears the license type from Revit 2021 (and others 2019 and up, if you customise it). This is helpful if you were originally using an onsite license sever(s) and have now switched to user based licensing and the user forgot or wasn't able to switch their licence type.
I used these links as reference:
Autodesk Product Key Lookup
How to reset a licence
*.BAT file is named:
ALR-Revit 2021.bat - ALR just stand for Autodesk Licence Reset and file is stored in the PackageShare\Scripts directory.
*.BAT file contains (For my 2021 example):
"C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\helper\AdskLicensingInstHelper.exe" change -pk 829M1 -pv 2021.0.0.F -lm ""
*.BAT file Options:
"C:\Program Files (x86)\Common Files\Autodesk Shared\AdskLicensing\Current\helper\AdskLicensingInstHelper.exe" change -pk PRODUCTKEY -pv VERSION.0.0.F -lm ""