Portable interwiki is a program I imagine. It is some sort of web browser extension. Its scope is wikis. Mycorrhiza wikis specifically, I suppose. The idea is simple. It shows how many backlinks the hypha on screen has on your wiki, which might be very private and secret.
When Mycoverse comes, there might be interwiki backlinks, sure. But they will come with delay, and private wikis cannot be part of it. This extension kinda solves it.