singleton-ops | Operations for primitive and String singleton types | Game Engine library

From the gradle java-plugin doc,

The api configuration should be used to declare dependencies which are exported by the library API, whereas the implementation configuration should be used to declare dependencies which are internal to the component. Dependencies appearing in the api configurations will be transitively exposed to consumers of the library, and as such will appear on the compile classpath of consumers. Dependencies found in the implementation configuration will, on the other hand, not be exposed to consumers, and therefore not leak into the consumers' compile classpath

Let's say of you want to expose eu.timepit:singleton-ops_${vs.scalaBinaryV}:0.5.0 to all of the common library then you need to add this as api dependency in common module build.gradle.kts.