rrdtool-tcl 1.7.0-0ubuntu3 (amd64 binary) in ubuntu bionic

 The Round Robin Database Tool (RRDtool) is a system to store and display
 time-series data (e.g. network bandwidth, machine-room temperature,
 server load average). It stores the data in Round Robin Databases (RRDs),
 a very compact way that will not expand over time. RRDtool processes the
 extracted data to enforce a certain data density, allowing for useful
 graphical representation of data values.
 .
 This package contains a Tcl interface to RRDs.