The EMERGE_WARNING_DELAY option is not mentioned in make.conf.5 in portage-2.2.0_alpha50. Reproducible: Always
Created attachment 282269 [details, diff] patch for adding emerge_warning_delay part to make.conf.5
This has been fixed since portage-2.1.10.41: http://git.overlays.gentoo.org/gitweb/?p=proj/portage.git;a=commit;h=a3c1e7f0c05f7be8507453324e178d041cb88796