How to make KEXT files open with Finder
Create an Automator Service using the setting in the image below.



Then assign it a keyboard shortcut in: System Preferences > Keyboard > Shortcuts > Services

I assigned it: optioncommandK

Code for Run Shell Script:

for f in "$@"
do
    fn="$(basename "$f")"
    ext="${fn##*.}"
    if [[ $ext == kext ]]; then
        open "$f/Contents"
    fi
done