When you download RPR for Blender for macOS from the website and install it the 2nd installer dialog is blank.
The first dialog after beginning the installer is this:
The second dialog is this... I don't know what to press.
This has been in every v1.7 installer for macOS and is still in the latest Mojave RPR 1.7.217 installer.
This bug was happening in High Sierra 10.13.6 as well.
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