The specifics I was referring to came from the B5 Wars tabletop game. As I said before, the E-Web existed only by implication in the show.
Here are the descriptions from the 2nd Edition Rules. Bolding is my emphasis, italics in original.
Page 48:
Shields are a defensive item used by Vorlons, some League races, and the Minbari White Star. They come in various types, but all have the same basic abilities. The shields used on the White Star are of the electromagnetic variety, and are often called EM shields . Other types include the gravitic shield used by the Abbai, some Brakiri ships, and a few other races....
Shields are protective devices that attempt to deflect some of the effect of incoming fire from striking the ship's hull. They have two basic effects: reduction of the chance to hit, and absorption of some incoming damage. EM shields do these things by producing an electromagnetic screen that partially surrounds the ship, while gravitic shields accomplish the same goal by warping space enough that incoming weapons are shifted slightly as they approach. Each shield system protects only a certain area (arc) of the ship, and if destroyed or deactivated, that leaves a hole in the defense screen that can be exploited by an opponent.
Page 72:
The Earth Alliance is one of the few powers to employ weapons dedicated specifically to an interception role. These weapons are highly effective at deflecting some or all of an incoming shot, as reflected by their high intercept rating....
In addition to their normal use as defensive weapons, interceptors also generate an energy web (similar to shields) which surrounds the ship. This web reduces the ship's defensive rating in all directions covered by the arcs of active (and undestroyed) interceptors. Thus, any ship equipped with interceptors will have two defense ratings for each direction, as shown in the example here. The first of these is in force only if there are no active interceptors which bear on the incoming fire. If, on the other hand, there is at least one interceptor facing the approaching shot, the second rating (in parenthesis) is used instead. Note that the second, interceptor-enhanced defense rating affects all weapons, even lasers!
Note: This does NOT mean that an interceptor can fire defensively against lasers. The energy web is a passive defense , like a weaker variety of shield, whereas defensive fire is an active defense
I'm looking over all the Agents of Gaming material I can find, and I could've sworn I saw the "E-Web" abbreviation used somewhere in them, but it looks like it was player-created jargon. As for using an old tabletop game as a source, here's a quote from the introduction to the 2nd Edition Rules Compendium by JMS.
When other licensees needed information on ship configurations or weapons capabilities, we referred them to the Agents of Gaming books (such as the one you are now holding in your hands). When we were in production and engaged in the writing of episodes or the mapping out of sets, if I was not available to answer a specific question on a technical area covered by AoG...the people involved were directed to go to the AoG books. Whenever AoG’s miniatures showed up on set, there was always a feeding frenzy of the sort usually associated with an unlucky cow falling into a river filled with piranha.
What I’m saying, in this roundabout way, is that if you want the Real Deal, if you want accuracy, canonical authority, and the best of the best when it comes to BABYLON 5 licensing and gaming... you’ve come to the right place.