Files imported into editor are stored as uasset then when you build an application the editor will “cook” those assets to optimize them for your application in uexp ubluk. They will be stripped down of some editor only data and optimized for runtime use.
You can load those assets directly in your runtime application.
You can also load them in your editor if needed: Working with Cooked Content in the Editor | Unreal Engine 4.27 Documentation
However your question means you need to look a bit more into your process.
Why do you want to open cooked asset in your editor? Cooked asset are not a good interchange file format.