Install
Upload it under Plugins → Add New Plugin → Upload Plugin, then activate.
Install straight from GitHub with WP-CLI:
wp plugin install https://github.com/martinandersen84/wprelay-extras/releases/download/v1.0.5/wprelay-extras-v1.0.5.zipUpdates itself. It ships its own updater (Plugin Update Checker), so new versions appear under Dashboard → Updates.
Releases
4 releases. Each count is every asset in that release; expand a row for the breakdown.