An official blog post announced the servers and funds that were keeping CM up and running would be discontinued on December 31st. Then seemingly out of nowhere, CyanogenMod’s website, wiki, forums, Gerrit, and download servers were all shut down thanks to a change in their DNS.
While LineageOS is still trying to get on its feet, they have been able to bring up their own Gerrit server now. For those who are unaware, Gerrit enables a team of developers to announce changes they would like to make to a code base. These changes can be viewed by other members of the team, and they can all comment on it as well. So before a bug is fixed, or a new feature is implemented, other developers can look at it and decide whether or not they feel it would create a conflict. This also gives people who are outside of the development team a way to see which type of changes are happening (assuming it has been made public). So you or I can go through the latest changes that are happening with LineageOS right now.