Never actually gotten my hands on symbology for the RWR before, generally they classify that stuff.
The outer ring shows heading and probably has something to do with estimating signal strength. The inner ring looks to be the threat ring. Flashing seems to indicate either being tracked or fired upon. The boat is the universal symbol for a boat. The question mark is probably an unknown emitter.
So the questions I have at least, are which symbol is a SAM, which is an airborne contact, and what do the circles mean? The circle probably relates to relative threat (notice both, what I'm assuming are launch warnings, happen when the circle touches the ownship cross), but the golden rule of RWRs is they don't show range, but signal strength, so idk.
As for which symbol is which, my current guess is the inverted triangles are surface threats (pointing down?), while the upward pointing ones are aircraft (look like jets), but I dunno. I could also see the upward pointing ones looking like SAMs.