As economist Milov mentions, >60% of Russia's cash reserves - the vaunted sovereign wealth fund - are to be released in December to finance the deficit.
But he was using the official figure of 2.12T Rubles, not the updated figure of 3.296 T.
Basically he's saying that Russia will need to drain over 92% of their reserves to finance this year's debt... which, btw, traditionally rises in Q4, likely draining the entirety of Russia's cash reserves... plus more, largely due to poor bond sales.