Dimension is a way for people hosting Riot to expand their integrations offering to their users.
Point your Riot config.json to Dimension to start using it:
"integrations_ui_url": "https://dimension.t2bot.io/riot",
"integrations_rest_url": "https://dimension.t2bot.io/api/v1/scalar",
"integrations_widgets_urls": ["https://dimension.t2bot.io/widgets"],
Learn more on Github. Talk about it in #dimension:t2l.io