open-browser | Open browser window and set proxy | Proxy library

No, you can not change actively running Selenium WebDriver session from normal to headless and vice versa.
In the similar manner you will not be able to re-define default downloading folder, no-sandbox, disable-dev-shm-usage etc.
All these parameters are loaded during the WebDriver object creating and can not be changed for existing, running WebDriver instance.

There is no blocking when calling Thread.start() in the way you suggest. The call is blocking in the sense that a call is placed that initalizes the new-thread internal state, and a system call is made to start the actual OS Thread - but that should take less than 1ms. The function that is the target of the thread is only called on the new thread, and the main thread will continue to run, regardless of what takes place inside that function.

If you want your program not to end, there is no need to resort to a complicated pausing loop like the one you setup - just place a call to threading.join() instead. This will block until all other threads end running, and only them the threading calling join() will proceed.

I get your question, I think you want to get only the url starting from https://, please correct me.

If so I think I could remove the deeplink url scheme myapp:// and the host open-browser/ like

Assuming that you are using chrome:

1. Install selenium by running in a terminal pip install selenium
2. Install a chromedriver via a manager (It allows you to control chrome) by running in a terminal pip install webdriver-manager
3. Create a file example.py and paste this inside

It has 2 independent processes: The GUI and the mitmproxy script. And communicating both processes does not imply importing modules since you would be creating another widget, also objects should not be accessed through classes (I recommend you check your basic python notes).

In this the solution is to use some Inter process communication (IPC), in this case you can use Qt Remote Objects (QtRO):

main.py

1. regarding the import of app.js inside index.js - you just need to write:

import helloWorld from './app.js';

and it's working!

1. As for node modules, this is more complicated. Usually on project set-up (take an automatic one such as create-react-app) there's a JS BUNDLER that is installed, like Webpack, rollup.JS Parcel etc. . Those, by the way, help you with js files references and imports... But once you create an empty project and than use npm install without a bundler or package.json and more configuration - it will be harder to import.

read this article about how to install modules on JS project

This link explains which browser is used for your addin. In Windows, it depends on both Windows and Office version: https://docs.microsoft.com/en-us/office/dev/add-ins/concepts/browsers-used-by-office-web-add-ins

For cases where, Edge is used, urls open in a dialog window (instead of default browser) when the url is the same or a subdomain of the source location, or when the url is in the AppDomains of the addin manifest https://docs.microsoft.com/en-us/office/dev/add-ins/outlook/manifests#app-domains. To work around this to open the url in browser window, you can try openBrowserWindow discussed here https://github.com/OfficeDev/office-js/issues/712.