With the CW starter indoor map, what exactly happens with broken glass? Does it still produce rubble? Does the entire connecting series of walls shatter? I'm thinking the former applies, but it seems a little awkward to make hindering rubble out of glass walls.

Only the parts of the glass wall that had a LoF drawn through it is destroyed. And since the special rules for glass walls doesn't say anything about rubble it'll work just like with regular walls. So a destroyed glass wall creates rubble.

Thank you, and apologies for not quoting. I keep forgetting how helpful that is.