The December 2022 helpful content update began rolling out on December 5, 2022; Google announced it the next day, saying it was "starting to become more visible" and would take about two weeks to fully roll out. It ultimately took 38 days, completing on January 12, 2023, per the Search Status Dashboard. Like the December 2022 link spam update running alongside it, the rollout stretched across the holidays, when, as Google's Danny Sullivan put it, "rollouts can slow or pause".
The update did two things. It extended the helpful content system to content in all languages globally, where the original August 2022 launch had covered English only, and it improved the system's classifier, with Search Engine Land noting it added signals to help Google identify more content created primarily for search engines rather than for people.
The helpful content system works as a sitewide signal: it targets sites with a relatively high amount of content created primarily to rank in search engines rather than to help or inform people, so a hit tends to weigh on a whole site rather than individual pages. Sites that slid during the December 5 to January 12 window were advised to audit for unhelpful, search-engine-first content and reorient toward people-first material.