GLEP 68 contains a link to https://projects.gentoo.org/pms/6/pms.html#x1-166000A which is broken, however. I suggest updating to https://projects.gentoo.org/pms/5/pms.html#x1-163000A (since in the EAPI 6 version Appendix A links back to GLEP 68).
Thanks, fixed.