Well, now WotC has released a smattering of info about the game, which it will tease in mid-2018 at Comic-Con International and Gen Con with a four-card Convention Edition pack that gives owners a few exclusive cards without giving them enough to play the game. The two-player Autobots Starter Set and Booster Packs will debut on September 28, 2018, and the game bears this brief description:
• Shortly after announcing combined sales of 320,000 copies of Azul across 25 languages, Next Move Games has announced its next release — Azul: Stained Glass of Sintra, a standalone game from Michael Kiesling that will debut at SPIEL '18 in October. From the image and short description, gameplay seems akin to Azul in how players draft tiles from a shared space, but then things diverge from there:
Players can expect to discover new unique art and components in Azul: Stained Glass of Sintra, including translucent window pane pieces, a tower to hold discarded glass panes, and double-sided player boards and window pane panels, in addition to many other beautiful components!
As for Sintra, a little research shows that the Pena Palace in Sintra, Portugal "holds the totality of the stained glass collection of King Ferdinand as well as a very significant proportion of his glass object collection", according to the Parques de Sintra website, with this company having been formed in 2000 to merge "the different institutions holding responsibilities for safeguarding and valuing the Sintra Cultural Landscape". The more you know...