AssetBundleKey
assets/asset-bundle.types.ts:19The union of valid key arguments for a bundle with entries E — its
string keys. Used to type BoundAssetBundle.get and friends so a
mistyped or undeclared key fails at compile time.
keyof E & string 
The union of valid key arguments for a bundle with entries E — its
string keys. Used to type BoundAssetBundle.get and friends so a
mistyped or undeclared key fails at compile time.
keyof E & string