You can open .DAT files that contain text, with text editors, like Notepad, Notepad++, VS Code, etc. But it is not possible to know what contains in a DAT file.

If you're having trouble opening a DAT file, I'll show you a simple and free way to do it. This method works on both Mac and PC. Just open your browser and go to winmaildat.com. It's a ...

*.dat files are just a generic label for data files, they arent actually a standard type, it can have ANYTHING in it, that being said theres almost definately a dat file editor for age of kings ...

A little-known Windows feature will create a file that stores text extracted from all the emails and plaintext-files found on your PC, which sometimes may reveal passwords or private conversations.