macOS install dmg, filename: 'Readme.rtf'
The last paragraph in the rtf doc contains incorrect information. Specifically, the last part of the first sentence ...
"- this requires opening the MakeMKV in Applications folder while holding an option key."
An option key is not used to launch a unidentified application. In fact, the specified Apple support article contains no mention of using the option key.
The correct method for quickly launching an Unidentified application is mentioned at the end of the referenced Apple support article. Which is ...
"If you're prompted to open the app in Finder and you're sure you want to open it despite the warning, you can control-click the app, choose Open from the menu, and then click Open in the dialog that appears. Enter your admin name and password to open the app."