This is the ControlPort package. It is a tool to create distributed control applications for GNU Radio. It provides blocks that can be connected to an output stream to plot the signal remotely. It also provides an API that allows blocks to export variables that can be set, monitored, and plotted remotely.
ControlPort-specific functions and utilities are found in the 'ctrlport' namespace. From Python, access is done using the gnuradio.ctrlport module, imported as:
ControlPort is currently a temporary stub implementation of a set of RPC calls we would like to enable that would allow remote viewing, command, and control of GNU Radio flowgraphs and blocks.