Chrome had it, but they killed the feature a few years back and are intentionally not bringing it back because of the low user adoption. There are some hacks t

Chrome had it, but they killed the feature a few years back and are intentionally not bringing it back because of the low user adoption. There are some hacks that open a new window with tabs, and resizes the main window to put it side by side, but it doesn't feel right. Or at least that was the case the last time I looked a year or two ago. Edit: also, yes, from what I understand, the WebExtenstions Api in Chrome does not allow these modifications.