When I'm surfing on Internet I do like to have a quick look at the code of at least one page before leaving websites I visit. But there's something I see often and ( that may be for security purpose but I want to be sure) is that the name of assets (js, css, and so on) can contain a randomized part.
This is an example in the source code of a page from GitHub:
<link rel="stylesheet" media="all" href="https://assets-cdn.github.com/assets/frameworks-0d3df748b8f66933615db469504dcd2c686fccb2772bc4e7263abb77014b7bc3.css" crossorigin="anonymous">
Can anyone explain the reason of that practice, please?