the gdb info "Contributors" page reads: "GDB uses the BFD subroutine library to examine multiple object-file formats; BFD was a joint project of David V. Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore." i don't think gdb uses the BFD libs anymore. those libs are part of the binutils-devel package, which are not a prereq of gdb, as far as i can tell.
gdb-X-Y.src.rpm contains gdb-X.Y.tar.bz2 which contains gdb-X.y/bfd subdirectory containing the BFD library. GDB functionality is based on the BFD library. Due to a complicated API/ABI compatibility of BFD it is bundled with each package separately - both with GDB and with BINUTILS. It is built statically with GDB so you do not see it even by ldd(1).