xampp-portcheck.exe is a self running archive file and so can be opened in 7-Zip, WinRAR etc.
It contains several files one of which is a Visual Basic Script called checkports.vbs that when viewed in 7-Zip, WinRAR etc. will reveal the Mercury entries you see in the captured shell window you posted above.
It is possible to edit the vbs file but only after extracting the files.
Change all the Mercury entries to hMail or what ever you like then save the file and drag it back into the open archive.
Just edited the vbs and tested it myself and it seems to work fine with Mercury replaced by hMail in the shell window.
Good luck and best wishes.