On Fri, Jul 1, 2016 at 8:53 AM, Purodha Blissenbach
"Wikibookses" bodes strange to me, yet I am not a native English speaker.
That piece was added by a native speaker of English (not me). :) If we
consider e.g. "English Wikibooks" to be in the singular form, as a
"Wikibooks" rather than "books" being plural", then, as it ends
sibilant sound, -es would be a sensible way to construct a plural form
for it. But I might edit that slightly prior to sending it out on
Monday to avoid confusing non-native speakers.