• The name of the app in the title bar of the window is MiTeC Mail Viewer
• The name of the app in the "About" window is Mail Viewer
• The files you download are a zipped EXE (so there is no installation needed)

Here the information extracted from the EXE file:

File name and path:     D:\PortableApps\PortableApps\_WSCCPortable\MiTeC Utilities\MailView.exe
Product Name:           Mail Viewer
Internal Name:          
Original Filename:      

File Description:       Message Database Viewer (OE, Win/Live Mail, Mozilla Thunderbird)
Company:                MiTeC
Legal Copyright:        Copyright (c) 2009-2017, Michal Mutl
Legal Trademarks:       All right reserved
Comments:               

File Version String:    2.3.0.625
File Version:           2.3.0.625
Product Version String: 1.0.0.0
Product Version:        2.3.0.625