A large library that assists in mod creation.
Editors were moved to BeardLib-Editor a while ago, get them there BeardLib-Editor
The main documentation can be found on the wiki.
You can find them here: https://github.com/ModWorkshop/BeardLib-Templates
I'm not sure which version of the upgrades lead to this ,because I found that there have been several recent upgrades. And I haven't played this game much lately.