val docTargets by extra(mutableSetOf<String>(
    // remove those you don't need
    "slides",
    "handout",
    "notes",
    "examples"
))

val slidesImages by extra(mutableSetOf<String>(
    // example:
    // "image1.png",
    // "image2.pdf",
    // "image3.pdf"
))

val generatedImages by extra(mutableMapOf<String, String>(
    // key = destination, value = source
    // example:
    // "image2.pdf" to "image2.svg",
    // "image3.pdf" to "image3.R"
))