I wrote this after I saw a reddit post about something similar, but it required some work to trick the built-in heatbed timeout feature in the Prusa firmware. Essentially it moves the print head 0.1 mm every 29 minutes to avoid the 30 minute timeout.
I commented the code so you can easily adjust the temperature to your liking. For typical sourdough bread you want it at 27°C (80° F), but since it only heats the bottom I bumped the default up to 32°C to compensate.
Generally you shouldn't trust G-Code uploaded by strangers, but I inserted comments everywhere to explain what's happening.
The author marked this model as their own original creation.