Manually Install [Export Security Role] tool on XrmToolBox

Download the file from below link:

https://github.com/arshad1234517/Export-Security-Role-File and add the dll under the xrm tool box.

Then go to the configuration click on the setting  select the path take that downloaded file and click ok 

Step 6: Now click on the export security role then click on the retrieve role then select the which role you want to export into excel file.