When you click on the reply button to a comment on a pull request...nothing at all appears to happen. (At least not for me, using Firefox on Rawhide with ublock origin and umatrix, but no JS seems to be being blocked). At first I thought it was broken, but it isn't, it works 'fine', by populating the actual text entry box for the next comment with the quoted text of the comment whose reply button you clicked. But it doesn't indicate to you in any way that it has done this - there's no visual feedback at all if the text entry box isn't actually visible on screen when you hit the button. Because there's no indication that this has happened, you may just give up, or keep hitting the button, which seems to keep appending the text to the box over and over...