It expects coverage to be an array of filepaths to LCOV files.
It allows sourcemapped to be an array of file patterns that may contain sourcemaps to the files in the directory where coverageconfig.json is placed.
Due to code coverage being applied to transformed files in JS, there is often a difference in the generated files that are executed and the original source files that a developer edits.
You can view the example/server/ as the development files and the example/out/server/ as the generated files while using the plugin.