There is a new forum post on the North American WoT forum where a mod is elaborating on prohibited mods. It does effect at least one mod in Aslain.
Mods that show which tank caused incoming damage, specifically if that tank was not spotted, are considered 'illegal'. This includes:
Mods that show which tank caused incoming damage: (All confirmed to show even unspotted tanks.)
Damage Panel GambitER 0.9.6
Zayaz Battleinferface 5.05
Xft DamagePanel + integrated hitlog
Mini Damage Panel by Nikodemsky
Safe (Does not show which tank):
SeaFalcons Damage Panel + Hitlog (glow version)
The relevant post.