Yes, I think it was enabled by default when I installed NodeBB:
A Markdown parser for NodeBB
Installed 8.9.2 | Latest 8.9.2
I know it's a plugin, but it's a pretty serious bug in my opinion.
The local email plugin is giving me a "page not found" in the ACP!
Not Found You seem to have stumbled upon a page that does not exist. Return to the home page.
@Giorgio-Chiodi Have you restarted nodebb?