repoman -h say about IUSE.invalid This ebuild has a variable in IUSE that is not in the use.desc or use.local.desc file which better should be IUSE.invalid This ebuild has a variable in IUSE that is not in the use.desc or its metadata.xml file or similar
Created attachment 207453 [details, diff] patch
Thanks, this is in svn r14681.
This is fixed in 2.1.7.2 and 2.2_rc47.