The Teddy Saviour T-shirt is a reward from the Covert Cryptographer achievement in Issue 7.
You have the opportunity to get a toy bear while doing the whiteboard part of the “I Walk Into Empty” mission.
Note: The toy rewarded is random. Confirmed bears are Raggy (above), Ruffy, Einstein and Spencer; not sure if there are other bears. The toy does not follow like a “pet,” instead they will remain where summoned and then fall forward before despawning when the player moves away. Each bear is tagged as Unique, but with some luck you can eventually collect different ones. If you really, really want some hints, spoilers are on the forums. Read at your own risk!
Thank you Cola, Vomher and Claudia for the screenshots!