The primary use of component URLs is to identify a component in the definition of a component instance, as part of a child declaration.
You should not use component URLs to identify component instances, as multiple component instances can share the same URL. For that purpose, instead use monikers.
A component URL can, in principle, have any scheme. Some common schemes you may encounter are:
fuchsia-boot component URL locates a component in the system boot image. This scheme is used to identify components that must be resolved during early boot before a
fuchsia-pkg resolver is available. It has the following format:
http(s) component URL identifies a web page as a component. Such a component could be executed as a web page in a web runner, for example.