Finding Google AdSense publisher ID’s (any tools for the job?)

I know there is a website that shows the different websites using a particular AdSense publisher ID (that website is http://host.io/), but is there also a website or web tool that automatically shows you the AdSense publisher ID of any website utilising Google AdSense?

I’m using a MacBook (I’m new to it as I’ve always used a PC), and I’m struggling to locate where I can find the AdSense pub ID on a website? I can’t find any developer tools on Safari web browser and then when I downloaded Google Chrome to use “Developer Tools” I still couldn’t find the AdSense publisher ID.

Any help would be greatly appreciated!

It's easy to find any website's AdSense Publisher ID via website.com/ads.txt or using chrome extensions unless the website owner has hide their Publisher ID manually!

Still you can try searching "c-pub" via Inspect option on Chrome!