This is a pack of two existing WA's modified to work with Dragonflight. One is showing an icon on the nameplate if the mob is not stunnable and one is showing an icon on the nameplate that changes color based on stun DR.
The icon showing if a mob can't be stunned is dependent on the data existing in MDT (right click on a mob in MDT to see if it can be stunned). Any false positives/missing data is because the data is not in MDT yet.
Credit to the original creators: