This is the default theme built into retro-go at compile time.
It can be used as a template to create a new theme.
The theme.json provided here is meant to be used as a reference when creating a new theme. It might not always be up to date with the actual default theme. Modifying it here won't impact retro-go either, you have to change the code for that.
The actual values used in retro-go are hard coded in the code in the following places: