Download KindleShare.zip, unzip it, move KindleShare.app to /Applications, then run xattr -dr com.apple.quarantine /Applications/KindleShare.app if macOS blocks the app.
Download KindleShare.zip, unzip it, move KindleShare.app to /Applications, then run xattr -dr com.apple.quarantine /Applications/KindleShare.app if macOS blocks the app.