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
GDB is a portable debugger that runs on many Unix-like systems and offers extensive facilities for tracing and altering the execution of computer programs. The user can monitor and modify the values of programs' internal variables, and even call functions independently of the program's normal behavior. It uses a system call named ptrace (the name is an abbreviation of "process trace") to observe and control the execution of another process, and examine and change the process's memory and register.
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/