Apparently, it's supposed to recognise phone numbers and seems to come from the Elementor WordPress builder, which would explain why the same regex occurs so frequently. It also seems that the code is embedded as hidden on many, many pages, further boosting the number of hits since my analysis cannot tell the difference between a visible and an invisible element. Elementor offered no straightforward way to report this bug, so I gave up.
Here are common examples you'll run into across the difficulty levels:
，推荐阅读谷歌浏览器【最新下载地址】获取更多信息
Последние новости，这一点在币安_币安注册_币安下载中也有详细论述
Раскрыты траты россиян на путешествия в Международный женский день20:37