There are a lot of edits deleted from the edit history so that is suspicious. however the changed text was in the description of the featured article which is on the homepage of the app. As far as I know a editor has to custom set them (as they are often slightly diffrent than the actual beginning of the article). So perhaps your thought about editor creds might make sense
edit: to clarify the reason I think it might be a app hack of some type is this text did not appear on the featured article from the browser version of Wikipedia
