I have a few questions about potential lines of sight on this map. The non-yellow barrel stacks near the SW corner have 2 LoS dots on them. I'm pretty sure this is considered a single area, are you considered to have a LoS if you can draw from either dot? Yes, some areas have two LoS markers. You have LoS if you can draw a line to either one.
Does the whole Level 2 ledge from the eastern side has a LoS to the Level 0 floor if it can draw a LoS? My guess is yes but there are no "Bs" at all on the floor so it makes me wonder. The ledge itself is not considered a wall so LoS looks clear.
Lots of LoS dots won’t have letters, but again, as long as you can draw a line to it (avoiding promontories) you have LoS.