Given everything that's gone before, I'm going to assume we can decipher whatever this is and approach it as a puzzle to solve. Whether it's a language, numbers, faction logos or rank insignia, it's there for us to solve. I realise it may not be, or that it may be something that can only be unlocked later, but there's no harm in trying.
Things to consider:
Since the Thargs seem to love octals, then it's safe to assume that whatever this is it's probably got something to do with an octal format (even if it's a rank logo, ours are bilaterraly symettrical because we as humans are too so it's natural to think that way, maybe the Tharg logos are 4 or 8 planes of symmetry, or something like that, for example)
If it's a Rank insignia or some other marker similar to our badges:
There's a LOT of them, and they aren't necessarily progressive (in that there's common elements among several and there's not much obvious progression from one icon to the next in most cases). I'm also assuming the collection we have here isn't all of them.
If it's something like a name or ID:
There's enough complexity in there for these to be words, however, where do you start translating it? If we go with the previous Thargoid signals, they have all been translatable into the maths that we know, one way or the other, so if we use the same approach here then these icons should be translatable into our English alphabet, presumably.
If it's not words/numbers:
It may be icons representing maps of an area of space, or planetary systems, there's no doubt that the "barnacle" core icon does resemble Barnard's loop or the Greater magellanic Cloud. Is that just because they are
really obvious structure in the sky and the Thargoids like it, or is it just a coincidence and the icon doesn't actually represent anything like that at all.
Non-Cannon Sources
There's a lot of misinformation out there about various things. I don't know if this stuff about the two Thargoid races is real or not. In the source material it's considered to be true, but they don't really know for sure and the whole plot of those novels is about layers of conspiracy, lies and deception. In the original Elite story the name "Thargoid" came from the first encounter, someone thought they saw the words "THARG" written on the side of the ship in an alien-ish alphabet and the name stuck. I don't know if that is still (or was ever) cannon but bear in mind that assuming things from any source (even official ones) might not actually be accurate (the official source might be lying, or might be making stuff up to hide the truth, etc.)