Where can I see people building large software products?

I am looking for resources online where I can see the software development process for large applications such as text editors (Sublime Text, Atom etc), web browsers or any other big piece of software. I want to be able to see the planning as well as development stages. This can be in any form, be it video or articles. Most tutorials I see in places like YouTube only show development of small projects like todo webapps. I would like a serious software development project. Thanks