[yocto] Build error while following Appendix A. Yocto Project Development manual

[Jim Abernathy]

I'm noticing fetcher failures while my bitbake is working. They are
listed as warning. Do I ignore these??

WARNING: Fetcher failure for URL: 'None'. Fetch command export
HOME="/home/jim"; export SSH_AGENT_PID="1500"; export
SSH_AUTH_SOCK="/tmp/keyring-Zcbzax/ssh"; export
GIT_CONFIG="/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux/usr/etc/gitconfig"; export PATH="/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux/usr/bin/core2-poky-linux:/home/jim/bsp-test/poky/build/tmp/sysroots/mymachine/usr/bin/crossscripts:/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux/usr/sbin:/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux/usr/bin:/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux/sbin:/home/jim/bsp-test/poky/build/tmp/sysroots/i686-linux//bin:/home/jim/bsp-test/poky/scripts:/home/jim/bsp-test/poky/bitbake/bin/:/home/jim/bsp-test/poky/scripts:/home/jim/bsp-test/poky/bitbake/bin/:/home/jim/bsp-test/poky/scripts:/home/jim/bsp-test/poky/bitbake/bin/:/home/jim/bsp-test/poky/scripts:/home/jim/bsp-test/poky/bitbake/bin/:/home/jim/poky/scripts:/home/jim/poky/bitbake/bin/:/home/jim/poky/scripts:/home/jim/poky/bitbake/bin/:/home/jim/CodeSourcery/Sourcery_G++_Lite/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/jim/bsp-test/poky/scripts"; /usr/bin/env wget -t 5 -q --passive-ftp --no-check-certificate -P /home/jim/bsp-test/poky/build/downloads 'https://fedorahosted.org/releases/l/i/liberation-fonts/liberation-fonts-1.04.tar.gz' failed with signal 4, output:

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