All this information in stored in the active file, which is rather large, as you might surmise. A structure that specifies the backend, the server and the virtual server settings. A named select method. Most groups store data on what articles you have read. This is the opposite of ephemeral groups.
All groups listed in the group buffer are solid groups.
The first article in a thread is the root. It is the ancestor of all articles in the thread. An article that has responses. A collection of messages in one file. The most common digest format is specified by RFC 1153.