GW has randomly posted an Eldar FAQ update for June, perhaps in anticipation of errors already in the Codex? Regardless, it refers to the weapon profile of the Shadow Weaver which will shed some light onto Warp Spider and Night Spinner weapons as well as Support Weapon Batteries.
Specifically, the link can be found here until/unless GW takes it down.
Reference – Profiles, Ranged Weapons
Replace the Shadow Weaver's profile with the following.
Shadow Weaver Range 48" S 6 AP 6 Type Heavy 1, Barrage, Blast, Monofilament
-Notice how it is a Heavy weapon and has the Monofilament special rule? This probably means that Support Weapon Batteries will remain Heavy weapons and that anything that uses Monofilament as a weapon (i.e., Warp Spiders, Night Spinner and Shadow Weaver) has this special rule.
-As far as the Night Spinner went, it was Rending and models hit were in Dangerous & Difficult terrain. This probably means that Warp Spiders will have this set of rules as well so we can probably look forward to Rending S6 AP6 Warp Spider shots and the Dangerous+Difficult terrain is a nice bonus too!
What do you guys think?