I don't think he has pre-soldered breakouts, period.
I question the relevance. I have barely used the SD card slot on my original Espruino's - I always find myself wanting byte oriented file storage, and the trouble and overhead of the file system on SD cards is a real bummer. And there are oodles of micro SD breakout boards.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I don't think he has pre-soldered breakouts, period.
I question the relevance. I have barely used the SD card slot on my original Espruino's - I always find myself wanting byte oriented file storage, and the trouble and overhead of the file system on SD cards is a real bummer. And there are oodles of micro SD breakout boards.