Drag emails into a web app from Outlook?

In modern times you should be able to drag an email out of Outlook, I'd imagine in an .msg file format as that is what the emails there become when you manually save them off, to a file upload control in HTML at a web application. (An .msg file is like an .eml file only Outlook specific. These keep individual emails. .eml is more generic. Outlook Express and Thunderbird use the .eml thing.) I get that from this which says partway down "Microsoft Edge (as of Windows 10 1709) and Google Chrome (as of version 76) natively support drag and drop from Outlook on Windows. If you use one of these browsers, then this plugin is not necessary." in, um, referring to a plugin I don't need.