return getProjectSelectors(pa -> !pa.optional && pa.active);
    }

    /**
     * @return Optional active project selectors, never {@code null}.
     */
    public Set<String> getOptionalActiveProjectSelectors() {
        return getProjectSelectors(pa -> pa.optional && pa.active);
    }

    /**
     * @return Required inactive project selectors, never {@code null}.
     */