What to add to the registry to add a file type association?

Question

Windows Registry

What you need and where to add so that specific extensions open at startup in, for example, a text document (C:\Windows\notepad.exe)

Answer 1

https://stackoverflow.com/questions/52008516/how-d...

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\${EXT}
HKCR\${EXT}