Open Graph is a protocol which enables rich previews on social media. It is heavily used on the web and different messenger apps. See https://ogp.me
Mycorrhiza Wiki supports it and outputs the needed meta tags to enable previews.
The name is hypha's name.
The image is the first image hypha embeds. If the hypha is an image, that image is shown. If there is no image, favicon is shown instead.
The description is hypha's first paragraph.
The author suspects the protocol is not being developed anymore. We're fine with that.