They're for presale, and according to Spotify's Twitter, they're automatically generated/sent via email to a select few of their "top" fans. But the codes are not unique and they work for all the dates, so they usually leak. My friend found the code for Jenny Lewis pretty easily, but so far no luck here.
edit: If I see one I'll share the love.
Edited by Kat Saunders, 10 April 2019 - 07:27 AM.