Powershell doesn't really have "builtins" per-se, every cmdlet is executed in the process of the shell itself but they're all contained within loadable modules (though 2-3 modules are loaded with the shell startup by default), Invoke-WebRequest is contained within Microsoft.PowerShell.Utility for example.
And zsh: http://zsh.sourceforge.net/Doc/Release/Shell-Builtin-Command...
Powershell doesn't really have "builtins" per-se, every cmdlet is executed in the process of the shell itself but they're all contained within loadable modules (though 2-3 modules are loaded with the shell startup by default), Invoke-WebRequest is contained within Microsoft.PowerShell.Utility for example.