`lcovonly` does not create `lcov.info`

[mrdgo]

karma.conf.js:

    karmaTypescriptConfig: {
      bundlerOptions: {
        entrypoints: /\.spec\.ts$/,
        transforms: [
          require("karma-typescript-angular2-transform")
        ],
        compilerOptions: {
          lib: ["ES2015", "DOM"]
        },
        reports: {
          lcovonly: {
            directory: 'coverage',
            subdirectory: '.',
            filename: 'lcov.info'
          },
        }
      }
    },

the file coverage/lcov.info is not created. Though the coverage report in html for the respective browser is there.

Versions:

• karma-typescript: 5.5.2
• typescript: 4.5.2
• karma: 6.3.9
• karma-coverage: 2.0.3
• jasmine: 3.10.0
• angular: 11.2.9