IS7 uses the same language as the Voynich manuscript. It is an illustrated codex written by an unknown author in an unknown language using an unknown alphabet. It remains undeciphered
A conversation I had today lead me to realize not everyone knows this, but one of my favourite threads in the Leithanien storyline is that it's retracing the changes between the Classical era of classical music and the Romantic, with Ebenholz being the most emblematic of this.