Romansh is a language that seems to be spoken only in the Swiss canton of Grisons. MessagesRm do no have any fallback set, which means that rm.wikipedia defaults to English, which is not any closer or similar to Romansh.
Translation statistics for Romansh are in pretty bad state, and the same happens with fur and ladin ones.
As such I propose to set $fallback for rm to 'fur' and 'it', or simply set it to 'it'; as it is more likely that Romansh speakers understand Italian than English.
Another approach would be to, given that Romansh is spoken in Grisons, check which are the second and third most spoken languages there and add them as fallbacks so their inhabitants could understand untranslated messages better.