[LamaOfRuin]

I believe they generally refer to themselves as open-core.

[lukan]

From this githubpage:

"Mattermost is an open source platform for secure collaboration across the entire software development lifecycle.. "

[throwaway89201]

But also: "open source" -> "open core" (9 months ago) [1]

[1] https://github.com/mattermost/mattermost/commit/0cc906d07e73...