Sometimes, you have some dynamic environment, where exist no direct connection between grandparent and grandchild processes. Also, you might want to prevent some messages from being injected in such systems.
I.e you want to communicate between browser page injected script and the native host: You can’t start native extension host directly from webpage, only background script can do that. You can’t send message from webpage, only content script can do that.
And the transports betwen those components are different too!
This is the usecase bifrostlink is intended to solve, it provides topology aware RPC protocol, which allows intermediate components to forward packets intended for other components.