For those like me who have no idea what this is about, here's the Chrome Web Store description.

Steam Inventory Helper: Provides many utilities for steam inventory and market (offers notification, quick selling, buying, offering trades, price check...)

The title as submitted to HN is a bit misleading. Should be "[...] monitoring every HTTP request"

At least they've stopped running "rm -rf /" on user machines (https://github.com/valvesoftware/steam-for-linux/issues/3671). So it's a step in the right direction.