When accessing an external translated page, External Guidance adjusts the content from the source wiki and provides entry points for contribution in the target wiki. The planned deployment (T216129) would allow access and contribution to any pair of languages.
In order to move more gradually, we want to introduce a temporarily limitation: only content translated from English or Simple English Wikipedia (into any language) will be affected by External Guidance changes.
In this way, users accessing a translation from English to Hindi will see the additional indicators and entry points to contribute, but it won't be visible for those accessing a translation from Japanese to Korean.
Once we assess the impact of the feature based on our metrics (T212414), we'll remove this restriction as a next step.