There seems to be no vertical scroll bar for the code snippets on Google Chrome on iPad, e.g.:
iOS (and macOS by default if a trackpad is in use) hide scrollbars when you are not scrolling an area. The scrollbar will be shown briefly when a scrollable view appears, then the bar will fade. For subregions which scroll, depending on the CSS, the scrollbar may not appear at all. SE do have control over this through CSS if they desire, by overriding the
::-webkit-scrollbar, but I don't think that's necessary.