Six locales times dark and light means twelve env files — is there a per-scenario way?

We ship in six locales and both colour schemes. As far as I can tell the locale and the colour scheme are properties of the environment, so covering the matrix means twelve envs/*.yaml files that differ in two lines each, and twelve run invocations.

That cannot be the intended shape. Is there a tag or a step that sets locale or colour scheme per scenario, so I can keep two env files and tag the handful of scenarios that actually care? Something like @locale:fr or @theme:dark.