gdb-doc 7.12.50.20170207-0ubuntu2 (amd64 binary) in ubuntu zesty

 GDB is a source-level debugger, capable of breaking programs at
 any specific line, displaying variable values, and determining
 where errors occurred. Currently, it works for C, C++, Fortran,
 Modula 2 and Java programs. A must-have for any serious
 programmer.
 .
 This package contains the GDB manual.