Two counts of oops, did not see the branding in photo 1. And I swear "retention" was misspelled the first time I saw it.

That is odd, that it's specific to the hub. The only other retentions I've seen similar to this are the familiar Schwinn "clips", and a spring-loaded release clip that bolts onto the fender eyelet on a couple Univegas. The common thread is the lack of "lips" on the dropouts.