Application crashes, software crashes and failures due to bugs in their programming result to coredumps. All information produced, log files and notifications which came from such crash events are saved in this directory.
According to /var/lib/systemd/coredump directory from February 11 - March 8 amounting to 1.5 G. To delete / clean the directory I have done this.
# rm -r /var/lib/systemd/coredump/*
Be sure to leave the coredump directory for systemd.