Part 2 of my Dark Angels Codex Supplement Review will take a look at the Detachment abilities that the army gains.
Models in the unit have a 5+ invulnerable save against ranged attacks. In your movement phase, if the unit remains stationary, it loses the save until the start of the next movement phase. If the unit advances, they gain a 4+ invulnerable save.
Ravenwing units in a Dark Angels detachment gain the Jink ability if they do not already have it.
This is a bike boost for the mobile units in the army. In the index version, only selected Ravenwing (non-codex) units got this ability, but it has been expanded to include all Ravenwing units. This includes Bikes, Outriders, Attack Bikes and Landspeeders, to name a few. This gives the Ravenwing units a big boost in durability for no increased points cost, which is a pretty good deal!
The Jink ability is also improved over previous versions, as you get it even if you don't get the first turn (a downside of the rule previously). This gives your Ravenwing unit a boost against enemy firepower, helping to survive the initial turn.
A great rule, which has been improved further with the codex.