GDB allows you to see what is going on `inside' another program while it executes -- or what another program was doing at the moment it crashed.
cd Ports/gdb
./package.sh
Website: https://sourceware.org/gdb
Port: https://github.com/SerenityOS/serenity/tree/master/Ports/gdb
Port icon has the following license: CC BY-SA 3.0 US by Jamie Guinan & Andreas Arnez https://sourceware.org/gdb/mascot/