Rhenish Franconian or Rhine Franconian is a dialect chain of West Central German. Wikipedia

Dialect family of West Central German Wikidata

One of two main subgroups of the West Central German dialects; spoken in Hesse, the southeastern half of Rhineland-Palatinate, northernmost Baden-Württemberg, and traditionally in Lorraine (France); distinguished from Central Franconian by the use of das (“that”) and was (“what”), and the pronunciation of Germanic -β- as a stop [p] when now in coda position. Wiktionary