Tiptap is a headless wrapper around ProseMirror – a toolkit for building rich text WYSIWYG editors, which is already in use at many well-known companies such as New York Times, The Guardian or Atlassian.
The pm package is a wrapper package for ProseMirror. This includes all ProseMirror packages that are required to run SSE Blog.
Documentation can be found on the SSE Blog website.