Thanks, Ana. I'll make sure to spread the word. FWIW, I'd like to see @Sahar Afshar talk us through variable fonts for justification in the Arabic script, perhaps someone else (Roozbeh?) could talk about the layout engine's struggles with that.
I'm probably missing your point but I'll expand on my suggestion nevertheless: I'd welcome a discussion of the possibilities of variable fonts for scripts other than Latin. I think exploration in this area has been rather sparse so far and the interaction between fonts and layout engine seems to be the reason the development of variable fonts for Arabic is stalled. I appreciate this might be common knowledge for you but it might not be for the majority of the TYPO Labs audience. If this topic isn't of interest for you, you can always sit that one out.
I'd be grateful to get a confirmation. Maybe @Ana Regidor can help? If it's common practice to send abstracts to conference organisers who don't officially call for proposals I think it would be fair to spread the word.
Glad you managed to make it work, Beau. For future reference: Just as in Igor's case I suspect the unicode ranges were not flagged correctly. If you happen to run into a similar problem, it's worth checking that first.