You think that Edge is closed source to avoid more bugs being found, but Microsoft also pays 3rd party developers for finding bugs in Edge?

You didn't answer my question at all. Are there any special reasons Edge has not been open sourced yet?

I didn't really understand what your question was, it sounded as if you were trying to imply the reason yourself.

I do not work for Microsoft, I have no insight into their decision making process. I doubt it has to do with security.

The JavaScript engine is open source:

https://github.com/Microsoft/ChakraCore