gitk 1:2.15.1-1ubuntu1 (amd64 binary) in ubuntu bionic

 Git is popular version control system designed to handle very large
 projects with speed and efficiency; it is used for many high profile
 open source projects, most notably the Linux kernel.
 .
 Git falls in the category of distributed source code management tools.
 Every Git working directory is a full-fledged repository with full
 revision tracking capabilities, not dependent on network access or a
 central server.
 .
 This package provides the gitk program, a tcl/tk revision tree visualizer.