User blog comment:B214/Talk About What You Want! 3/@comment-16281343-20150304112539/@comment-16281343-20150304115019

From Kadokawa's page of the limited edition.

From Ishi's blog, if I interpreted that correctly, it can be considered both as Episode 13 of Season 2 and Episode 0 of Season 3. In kadokawa's page, it was labeled as Ep. 0 of Season 3.

So, ep. 0 it is?