In roughly 1995, Taco Bell released their at the time newest flavor of "Border Sauce". It was called Wild Sauce. Initially, The sauce was kept in a crock pot and served warm, For $.99 it could be added to any of their entrees. The flavor was similar to their also fairly recent addition "Fire Sauce" but it was slightly tangy and severely more complex. After roughly a year they retired Wild sauce for a short time before releasing it in their signature sauce packet that you all know and love. Sadly, They only produced Wild Sauce in packets for a short amount of time.
In 1995 I was 5 years old. Also, this is the most professional sounding post about taco bell I have ever read. You clearly take your TB quite seriously and are quite knowledgeable of it's history. I don't know if that's impressive or not, but I'm entertained.