Component library
Every page in this section is generated from the same declaration the in-product Component Library (Setup → Component library) reads to draw its own copy — the placements a page may put a piece in, the inputs a page may set on it, what it raises, what can be read back off it, and a worked example. Neither page is authored separately, so neither can say something the other does not.
This section covers the 91 components the base library ships, and the 2 shared internals underneath them — pieces with no element to place, which every component above them is built out of and which therefore decide how the set behaves. A component that arrives in a package you install documents itself exactly the same way, on the same reference page, inside your own organisation — reachable from Setup → Component library once it is installed, because that page is where an installed set is a fact about your organisation rather than a public one.