The configuration of the @PLUGIN@ plugin is done in the gerrit.config
file.
[plugin "@PLUGIN@"] type = identicon
Can be any type supported by the service (404, mm, identicon, monsterid, wavatar, retro, blank, ...). Default: identicon
Uses the same protocol (http, https) as gerrit.canonicalWebUrl. Default: www.gravatar.com/avatar/
Default: http://www.gravatar.com