In Settings > Markdown, there's a list of plugins that the other can enable/disable. However, other than the name, there's no way to tell what it does, or how to use it. Like, what's "deflist syntax", why would I want it, and how do I use it?
It would be better for the average user if they had a way to tell what each plugin does, especially for the built-in plugins that ship with the app.
I recommend doing what Notepad++ does in its Plugin Manager, which is include a short description, author name, as well as the URL of the homepage of the project. Presumably N++ reads this info from some manifest file that's bundled with every plugin.
For anyone who finds this by googling, there's an explanation of built-in plugins here: Markdown Guide | Joplin
EDIT: the simplest way to solve this ticket, is to simply link the above page on the Settings > Markdown screen, if the fancy manifest plugin thing is too much work for now.