# Pastebin fbORNy8Z
$ grep -R GNU_MIRROR meta/conf
meta/conf/bitbake.conf:GNU_MIRROR = "https://ftp.gnu.org/gnu"
meta/conf/bitbake.conf:SAVANNAH_GNU_MIRROR = "https://download.savannah.gnu.org/releases"
meta/conf/bitbake.conf:SAVANNAH_NONGNU_MIRROR = "https://download.savannah.nongnu.org/releases"
meta/conf/bitbake.conf:    GNU_MIRROR \
meta/conf/bitbake.conf:    SAVANNAH_GNU_MIRROR \
meta/conf/bitbake.conf:    SAVANNAH_NONGNU_MIRROR \