in src/main/jbake/templates/includes/U.groovy [42:53]
def expandVariables(str, config) {
def pageVariables = [
sling_tagline : config.blog_subtitle,
sling_minJavaVersion : "8",
sling_minMavenVersion : "3.5.0",
sling_releaseVersion : "13",
sling_snapshotVersion : "14-SNAPSHOT",
]
// Use a closure to avoid exception on missing variable
str = str.replaceAll(/\$\{(\w+)\}/) { key -> pageVariables[key[1]] ?: "MISSING_PAGE_VARIABLE:${key[0]}" }
}