Converting chrome extension to safari web extension warnings

Hi,
I was trying to convert my chrome extension to Safari web extension, using the xcrun command, but when I did it, I got a warning about unsupported keys in the manifest.json, which are officially supported such as webRequest, host , storage etc.
I have a macbook pro with macOS big sur 11.2, safari 14.0.3 and Xcode 12.4.

Any idea why am I seeing these warnings?

Thanks