Chrome has a "new" headless mode in 109+ (technically added in 96 but it's the official way now) that makes headless Chrome behave much more like the real Chrome with UI and uses all of the same code. Of particular note for WebPageTest is that this makes the lighthouse audits (where headless is used) more accurate and fixes issues with the BF cache audit.
Chrome 112 (which is when the feature is officially GA) just rolled to stable. We have been using the new setting in the HTTP Archive for the past few months and highly recommend picking it up.
The official announcement is here: https://developer.chrome.com/articles/new-headless/ And indeed, the command-line flag/option has been available for longer, but it wasn't MVP feature-complete until M112.
This is a clean re-submit of https://github.com/WPO-Foundation/wptagent/pull/605
Chrome has a "new" headless mode in 109+ (technically added in 96 but it's the official way now) that makes headless Chrome behave much more like the real Chrome with UI and uses all of the same code. Of particular note for WebPageTest is that this makes the lighthouse audits (where headless is used) more accurate and fixes issues with the BF cache audit.
Chrome 112 (which is when the feature is officially GA) just rolled to stable. We have been using the new setting in the HTTP Archive for the past few months and highly recommend picking it up.