Chrome extension - How to know if own extension blocked page - manifest v3

Question

When blocking pages with a pattern like so:

chrome.declarativeNetRequest.updateDynamicRules({
  addRules: [
    {
      "id": 1,
      "priority": 1,
      "action": {"type": "block"},
      "condition": {
        "urlFilter": "*://*/*lala.js",
        "resourceTypes": ["main_frame"]
      }
    }
  ]
})

i get a page error:

ERR_BLOCKED_BY_CLIENT

What would be the best way to tell the user that my extension blocked this page?