The reply form used to render ~13 lines of hidden markup under every
top-level comment, so a 50-comment video shipped roughly 650 lines of
inert DOM to every signed-in viewer. Replaced with a single
<template id="ytc-reply-form-tpl"> plus a per-comment slot div; the
first click on Reply clones the template, wires the IDs
(replyForm{id}, replyBody{id}, data-parent-id, data-video-id) and
appends it, so toggle behavior stays identical from the user's side.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
