Old time Blues masters like Muddy Waters and Bukka White usually referred to Vestapol tuning (151351) with the major third tuned down a half step to the minor third as Cross Note Tuning (151b351)
Actually this is the same as Open Minor tuning. Although, they did not play a minor blues. Instead by fretting the third string, they had a major chord again. Lifting the finger was the same sound you get when playing in standard tuning, fingering an open position E chord and lifting your first finger to open the third string.
This tension between major and minor third is an important element in that blues sound. Although, not commonly associated with traditional blues, by tuning the third string up to g, the guitar is now in DADgad tuning. This is another very popular open tuning.
So, by just retuning one string in Vestapol tuning, you can play in 3 different tunings and create 3 very different musical ideas: DADf#ad...DADfad...DADgad.
I am using 151b351 tuning in this video. Key of C (CGCeflatgc) Listen, I pick out the minor chord at the end.