How to redirect a url to a local file with extension

Use declarativeNetRequest.

Debugging: https://stackoverflow.com/a/71277803

In manifest.json:

  "declarative_net_request": {
    "rule_resources": [{
      "id": "ruleset_1",
      "enabled": true,
      "path": "rules_1.json"
    }]
  },

In rules_1.json. The file must be within the extension, or served by local server...

Use this to get the url of the file: chrome.runtime.getURL("popup.html")

If it can't find the destination resource, or doesn't have permissions the status will show as "(blocked:other)" in devtools.

Success means original resource will show a 307 status code.

[
  {
    "id": 2,
    "priority": 2,
    "action": {
      "type": "redirect",
      "redirect": {
        "url": "chrome-extension://abckgldpfpiolkcgnkjjapplhgnjimmc/popup.html"
      }
    },
    "condition": {
      "urlFilter": "https://www.paypal.com/smart/buttons",
      "resourceTypes": ["sub_frame"]
    }
  }
]

In manifest.json provide permission to access local file in extension folder. Or you can just host it locally with localhost.

  "web_accessible_resources": [
    {
      "resources": ["popup.html"],
      "matches": ["*://*.jaanuu.com/*"]
    }
  ],