Hay is re-releasing Swiss industrial designer Bruno Rey's handsome Rey Chair, which first went into production in 1971. (Originally called the 3300, the chair took on its designer's name as it grew in popularity.)
The press release, and every design blog parroting it, mentions the chair's "innovative screwless production process," but no explanation of what this entails is mentioned. I poked around a bit and found this description, but no explanatory image, from the Museum für Gestaltung Zürich:
"The most successful piece of Swiss seating furniture of all time is based on an invention patented in 1972. [Bruno Rey] had been working for some time on an alternative to the conventional wooden frame chair. In his design, the chair legs are joined to the self-supporting seat by means of a bonded aluminum console that was handmade using sand casting in 1970/71 and afterward produced using the gravity die casting process."
Here's a shot of an original 3300 for sale on vintage furniture website Design Market, where you can see the "consoles," i.e. connectors, but again no description is given of how they're attached: