The official listing posted by the FVLB has the title of "Batman: The Enemy Within - Season Pass," with a rating of R13 for "Violence and content that may disturb." The key parts are the title itself, Batman: The Enemy Within, but also that the listing is specifically for the Season Pass.
Independently, the title could be taken as a a unique game or DLC for another product, but accompanied by the Season Pass labeling the Telltale association is too much to ignore. Of course, there's also the fact that the game is directed by Kent Mudle, Director at Telltale Games.
The first season of Telltale's Batman series was officially named Batman: The Telltale Series so its a bit odd that the developer's name is not somewhere in the title. Maybe Telltale will stylize it as Batman: The Enemy Within - A Telltale Series like they do with Minecraft: Story Mode.
For fans hoping for a Wolf Among Us 2 announcement at SDCC, don't give up hope yet. Telltale has made multiple announcements at past events before, and SDCC would be a great event to make multiple comic book-related announcements. Still, a second Batman series seems much more likely at this point than a second Wolf Among Us series.
The Fables spin-off adventure game is gorgeous, but the brand has fallen off a bit with the comic book run having ended. Never let up hope, though; this is the developer that started off with niche franchises, after all.
More Batman from Telltale is going to be highly anticipated, as the first series created a unique and gripping alternative to the traditional Batman origin lore. And in typical comic book fashion, left a dozen loose ends that fans will demand be tied together eventually. Until it's officially confirmed, however, consider the existence of Batman: The Enemy Within a rumor.
Stay tuned for more Telltale Games news, including a potential Batman: The Enemy Within announcement, during SDCC 2017 from July 20 - July 23.