From ai: Common 11-String Tunings

Extended Standard (Diatonic Basses): The most widespread tuning for the 11-string alto guitar features the top six strings in standard guitar tuning (E B G D A E from high to low), with additional bass strings descending diatonically (by whole steps/half steps) below the low E. A common example from high to low notes (1 to 11) is E, B, G, D, A, E, D, C, B, A, G.

As I thought .. extended