Alerts. That magnificent functionality in SharePoint, that let’s you get a heads-up anytime someone touches your precious documents (so you can go and revert the changes), or changes files in Style Library (so you can go and remove that pink custom CSS they tried to add). They are ancient, quite cumbersome and CERTAINLY not pretty, but quite reliable (and despite my expectations – they were included in Modern SharePoint, too!), so there’s really no reason to still keep using them.
However, every now and then, they’re quite hidden from the GUI. This post describes how to access them on pretty much any site!