Boilerplate pages use tokens to be customized for each site without needing to be rewritten. Basically, in the source post, instead of using actual data, you can place tokens. After publishing, tokens will be replaced by actual values on each child site.
The MainWP Boilerplate extension comes with a set of default tokens and the ability to create custom tokens.
For both default and custom tokens, it is required to set values for each child site individually, which will replace the token on child sites after publishing a boilerplate post or page.