The folks over at Chrome Story have spotted a commit to the Chromium Gerrit which points to a new "Never-Slow Mode" being worked on. It's described as "an experimental browsing mode that restricts resource loading and runtime processing to deliver a consistently fast experience," but at a cost: Google warns that it "may silently break content."

The commit dates back to last October, with more recent updates over the past week, and is explicitly labeled "PROTOTYPE — DO NOT COMMIT." So far as my weak Gerrit-parsing skills show, it hasn't been merged in just yet.

There's probably quite a lot of testing left to be done before it goes anywhere, as the commit's description describes blocking a wide variety of content including some scripts, assets like fonts and images based on size, as well as pausing page execution at times, among a larger list of content caps enumerated below:

Per-image max size: 1MiB
Total image budget: 2MiB
Per-stylesheet max size: 100KiB
Total stylesheet budget: 200KiB
Per-script max size: 50KiB
Total script budget: 500KiB
Per-font max size: 100KiB
Total font budget: 100KiB
Total connection limit: 10
Long-task limit: 200ms

All of this could easily break functionality in plenty of sites, but Google is still working on the feature — you can't even try it yet. Never-Slow Mode probably won't make a drastic dent in memory use, either, according to Chrome Story.

It's a bit concerning that Google might consider site-breaking changes to browsing like this, especially since Chrome/Chromium dominate the contemporary web ecosystem. Hopefully, by the time a feature like this is live, it can be integrated in a way that won't make web developers' lives any more difficult.