gdb-doc 11.0.50.20210630-0ubuntu1 (s390x binary) in ubuntu impish

 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.