Caddy web server no longer completely open source
github.com
github.com
The easiest answer would have been a "sure, here's the link". Instead the thread has been locked for being off-topic, yet the original issue and the question concern the same thing.
We are currently at a stage where we are getting feedback from the community on our current progress. If you want to be a part of that, feel free to reach out to one of us.
Yet since this issue got some more attention user "mholt" has changed the thread, now merely strongly claiming it were open source but not actually publishing or referring to the closed source portions, unable to confirm there were none and it were something innocuous like a backport from Go 1.13.
Nonetheless a use of force, him keeping the right to develop the discussion further to himself but denying the same to others.
Does Caddy run afould a LGPL? Is it about this? If you cannot bear sharing and the question "how did you solve this?", then don't claim to be an open source author.