#warframe exploration

The book has a very specific looking symbol on it & I thought it was kinda weird, but familiar? Running around more & I run into this. The locked door under the King's palace at the end of the tunnels has a similar symbol.

OK WAITWAITWAIT, I'm gonna need a tinfoil hat guys. SO, THE KAITHE RIGHT?? There's a statue of Thrax in the courtyard riding a Kaithe.. and the spear he's holding is POINTING AT THIS BUILDING.

AND OVER THE ENTERANCE OF SAID BUILDING, the symbol appears AGAIN.

As far as I've checked, NO OTHER BUILDING on the landing HAS THIS SYMBOL EXACTLY. There's ONE with it, BUT it's partially covered up, and I half wonder if it was mistakenly used? (ie. some level designer used the wrong door mesh?) Cause here are the other two door mesh designs.

Here is the weird one. This is on the LARGE building to the right of Extraction.