You gain a +1 bonus to AC while you wear this armor. You are considered proficient with this armor even if you lack proficiency with medium armor.
Elven Chain in the 2024 rules
The 2024 Dungeon Master’s Guide revised the magic items, and the SRD 5.2 carries the new text. What changed:
Same rarity and attunement; the text is reworded for the 2024 rules glossary.
Type
Armor (Chain Mail or Chain Shirt)
Rarity
Rare
Attunement
Not required
You gain a +1 bonus to Armor Class while you wear this armor. You are considered trained with this armor even if you lack training with Medium or Heavy armor.