A question came up this weekend about how Tactical Jammer works... I had put it on Han and was flying a B-wing behind... the text reads, Your ship obstructs enemy attacks. I took that a completely blocking line of sight. We played that way and everything flew well. Second match, my opponent was more "no, it doesn't block line of sight, it just obstructs like an asteroid, therefore you get one extra defense die".

and then proceeded to blow my B-wing up.

Question is, which way is it played? does it block line of sight or is it just an obstruction?

thanks

Attacks that are obstructed follow the rules as detailed in the Core rulebook page 20

Attacking Through Obstacles
Obstacles represent space features that are difficult to fire through.
When measuring range during combat, if the edge of the range ruler between the closest points of the two ships overlaps an obstacle token, the attack is considered obstructed.

Because of this obstruction, the defender rolls one additional defense die during the “Roll Defense Dice” step of this attack.

There is nothing in this game, except for Biggs, that can prevent an opponent from shooting a ship that is 'hiding' behind it provided that it is within range and arc.

If there is a cloaked Phantom entirely on the other side of a big rock you can still shoot at it provided it is within range and arc.

Yeah there is technically no 'line of sight' in this game. Just arc and range. Obstruction was covered above.

Another point to make is that an attack is either obstructed or not. There is no bonus to having 2 obstructions to a shot.