To be clear, this is where they see the list of add-ons:
In other work I’ve looked at adding a mermaid plugin - the current one in the marketplace is broken, as Atlassian now requires a POST to be done to register a plugin. The POST just sends a doc for
uninstalled and then a working implementation returns 200.
I tested a fix where I threw up a quick API endpoint in AWS using CDK and successfully registered the mermaid add-on. (Sorry, not for public use, at least not yet).