Can a plugin have non-JAR dependencies?

My plugin has a dependency that is not a JAR, but an artifact produced by another Gradle project.

I am unsure if a plugin can depend on arbitrary non JAR files.

Here is my plugin build.gradle:

dependencies {
    runtime project(path: ':otherProject', configuration: 'archives')

But when my plugin is applied, how can the plugin access those files?

void apply(Project project) {
  // How to get at those files in the runtime configuration?