X_CDP_LAUNCH_FAILED

the browser started and never announced a DevTools endpoint

Chrome is driven over --remote-debugging-pipe, so its first answer IS the announcement. It gets the launch deadline (60 s, or timeoutMs when that is larger) and, unanswered, is reaped and started ONCE more on a fresh profile. The cause carries each launch: whether it exited (with its code) or was still silent at the deadline, and its last stderr lines — D-Bus lines alone are start-up noise, so a deadline beside them is a machine too slow, an exit code a crash, a rejected flag or a sandbox refusal

/usr/bin/google-chrome --headless=new --no-sandbox --disable-dev-shm-usage --disable-gpu --remote-debugging-port=0 about:blank — the binary the cause names; a healthy one prints DevTools listening on ws://…