I am very peripherally involved with XR UK (Extinction Rebellion in the UK), and they have some custom software that does various administrative things.
I wanted to nose around, as I do with many bits of software, but found it's not open source, which surprised me, as it's part of an effort to use a suite of open source tools (mattermost, discourse, etc).
I asked about it, and got the "security through obscurity" argument back (what if the government can see it!!).
*sigh*
@nicksellen Oh, driven by distrust? Hm. Not good.
@nicksellen Mattermost is bloatware and you can't send private replies to people. That's why I created nlchat.
(https://organise.earth/uk/pl/uicmnypzi3837gk9z51ipxkyca is the thread if you're enrolled in the XR UK mattermost)