Chrome extension access to custom window variables

Question

I am using manifest v3 and trying to read window variable of the host

let tabs = await chrome.tabs.query({ currentWindow: true, active: true });
if (tabs.length > 0) {
    //let url = tabs[0].url;
    //console.table(new URL(url as string));        
    const tabId = tabs[0].id;
    chrome.scripting.executeScript(
        {
            target: { tabId: tabId as number },
            func: () => {
                console.log("test"); //printing test
                console.log(window); //printing window object
                console.log(window._spPageContextInfo); // undefined
                //window._spPageContextInfo.toString();
            }
        },
        (result) => {
            console.log(result[0].result);
        }
    );
}

I am able to access all default window variables but the custom variables generated by the SharePoint website. Basically I am trying to read sppagecontext Am I missing something?

here are permissions set in manifest.json

    "permissions": [
    "tabs",
    "activeTab",
    "cookies",
    "scripting"
  ],
  "host_permissions": [
    "http://*.sharepoint.com/"
  ],
  "content_security_policy": {
    "script-src": "self unsafe-inline unsafe-eval",
    "object-src": "self"
  }