This is how it works, each time you click on the Go back button to return on the serps page, the website displays a random internal page.
SOURCE: https://pastebin.com/GTcT61p8
Code:
window.history && window.history.pushState) { window.onpopstate = function () { let e = location.hash; var n = e.split("#!/")[1]; if ("" !== n && "" === window.location.hash) return locs.includes(window.location.pathname) ? window.location = locs[(locs.indexOf(window.location.pathname) + 1) % locs.length] : window.location = locs[0], !1 }; let e = locHref.split("?"); 1 == e.length ? window.history.pushState("forward", null, "./") : window.history.pushState("forward", null, "./?" + e[1]) }