Natively rendered scrollbars for applications
From https://github.com/xtermjs/xterm.js/issues/1875#issuecomment-453041344 (and subsequent comments):
If I understand the idea correctly, it's that many programs (e.g., emacs) have scrollback buffers. What if there were a control sequence that modified alternate screen mode so the scroll bars did not go through the terminal emulator's history, but instead instructed the app to display content at the scrolled-to region? Apps would need to report the size of their buffer in lines and the current offset, and the TE would need to report scroll events via some new report sequence.