Where does vscode-jupyter stores notebook->kernel associations

[mxposed]

Hi. In .ipynb format there is metadata.kernelspec object for storing the kernel that jupyter lab and jupyter notebook uses. However, I noticed that VS code doesn't use them the same way, and can't rely on it. Instead, it displays the correct name of the kernel, however that is absent from .ipynb file.

1. Where does it store it then?
2. Why does it not use metadata.kernelspec in the same way as jupyter UIs?