TimeTube.

A lightweight Chrome extension that injects watch-time intelligence directly into YouTube's native UI. Surfaces playlist totals, remaining time, speed-adjusted durations (1× to 2×), course classification, daily-watch planning, and an analytics modal — all computed locally via DOM scraping with zero external API calls. Built on Manifest V3 with Shadow-DOM isolation, stable ytd-* selector anchoring, coalesced MutationObserver injection, and a dual-tier cache (memory + chrome.storage).