internet_mapper_viewer/browser/background.js

function handle(requestDetails) {
    let b64 = btoa(requestDetails.url)
    if (!requestDetails.url.startsWith("http://localhost")) {
        console.log(`Loading: ${requestDetails.url} || ${b64}`);
        return {
            redirectUrl: `http://localhost:4433/s3/${b64}`
        }
    }
}

browser.webRequest.onBeforeRequest.addListener(
    handle, { urls: ["<all_urls>"] }, ["blocking"]
);