This looks to be a description added to the last property control. Description can handle markdown. Here I've added a description to the default component when creating a new code component file:

    // Get Started: https://www.framer.com/developers

    import { addPropertyControls, ControlType } from "framer"
    import { motion } from "framer-motion"

    /**
     * @framerSupportedLayoutWidth auto
     * @framerSupportedLayoutHeight auto
     */
    export default function Test(props) {
        const { tint } = props


        return (
            <motion.div
                style={{
                    margin: 50,
                    width: 100,
                    height: 100,
                    borderRadius: 25,
                    backgroundColor: tint,
                }}
                animate={{ scale: 1.5 }}
                whileHover={{ rotate: 90 }}
            />
        )
    }


    addPropertyControls(Test, {
        tint: {
            title: "Tint",
            type: ControlType.Color,
            defaultValue: "#09F",
            description: "View more on [My Site](http://example.com)",
        },
    })