The D65/10, A/10 and mlTL84 are the different light sources or illuminant as mentioned in the chart
DH – Difference in HUE (Colour)
DC – Difference in CHROMA (Is it brighter)
DL – Difference in LIGHTNESS
DE – The overall colour difference between the samples, in this instance we are looking for a difference in DC which is why we have highlighted it on the charts.