With so many different technologies created for web development, developers have tons of options to choose from to form their stack for their products. A web stack is simply a group of software that work together for a web app to function. If you are ever interested in what web stack a website uses, Wappalyzer has a website and a free web extension that scans a given website and lists all the technologies used.
I personally prefer to use the browser extension as it is more convenient. You simply go on a website you want to analyze, and then click on the browser extension icon for Wappalyzer. Below is a screenshot of what technologies my blog (and basically every WordPress blog) uses.
In this screenshot, you can see what services and products are used for both the front end and the back end. This could be informative if you are interested in knowing what stacks are used by which companies or are looking for ideas for what products you want to use for your own projects. As the extension is free, it is ready to be used the moment you install it on your browser.