The installation process can be controlled by setting properties on the command line. These are detailed below.
In general, only the "usual" properties are of interest. The advanced properties are listed for completeness and are like to be useful mostly to people writing installation packages (for instance Federation Operators).
The best & definitive documentation for these properties is the code itself.
Examples
Setting generated key size on non-Windows system
./bin/install.sh -Didp.keysize=2048
Setting generated key size on Windows system
.\bin\install.bat -Didp.keysize=2048
Setting installation directory on Windows systems
.\bin\build.bat -Didp.target.dir="C:\Program Files (x86)\Shibboleth\IdP"
Enable two additional modules during installation
install.bat -Didp.initial.modules=+idp.intercept.Impersonate,idp.authn.MFA