assertThat(formEncode(25)).isEqualTo("%19")
    assertThat(formEncode(26)).isEqualTo("%1A")
    assertThat(formEncode(27)).isEqualTo("%1B")
    assertThat(formEncode(28)).isEqualTo("%1C")
    assertThat(formEncode(29)).isEqualTo("%1D")
    assertThat(formEncode(30)).isEqualTo("%1E")
    assertThat(formEncode(31)).isEqualTo("%1F")
    // Browsers use '+' for space.

    @Nonnull
    Optional<Boolean> alsoMakeDependents();

    /**
     * Returns the number of threads used for parallel builds.
     *
     * @return an {@link Optional} containing the number of threads (or "1C" for one thread per CPU core), or empty if not specified
     */
    @Nonnull
    Optional<String> threads();

    /**
     * Returns the id of the build strategy to use.
     *