Binary package “gdb-source” in ubuntu focal

GNU Debugger (source)

 GDB is a source-level debugger, capable of breaking programs at
 any specific line, displaying variable values, and determining
 where errors occurred. Currently, gdb supports C, C++, D,
 Objective-C, Fortran, Java, OpenCL C, Pascal, assembly, Modula-2,
 Go, and Ada. A must-have for any serious programmer.
 This package contains the sources and patches which are needed
 to build GDB.