[pulseaudio-discuss] How to create a virtual microphone with source set as default monitor device?

[guest271314]

Chromium browser does not support capture of monitor devices when
navigator.mediaDevices.getUserMedia() is called. Chromium only
supports capture of non-monitor microphone input devices.

How to create a virtual microphone with source set as default monitor
device so that Chromium browser recognizes the virtual device as a
microphone while the source input for the microphone is the default
monitor?