The view and server modules are outside the site's generated API reference. Their documentation comments are in the source; this index lists each module, by package, and the page that covers it.
Builders: Element, VoidElement (whose View is the element as a view), ComponentTag, Attrs, Props, Events, Hooks, from, text, fragment, the control flow, render, renderOf, and Component.template, ofMembers, ofClass. Elements (generated): one class per tag.
Arms.Match, Arms.Prepare; on .NET BuildTimeReadException and ArmsMatchException (both inherit InvalidOperationException, which shared code catches on both targets)