emerge -pv gentoolkit [ebuild R ] app-portage/gentoolkit-0.4.6::gentoo PYTHON_TARGETS="python3_6 -python3_7" 0 KiB It seems that euse implies that there must be a new line at the end of make.conf, otherwise it would just delete the last line. Any variable you put at the last line would be deleted upon usage of euse. Reproducible: Always