Installed TTS voices imply an OS that contradicts the UA platform
br.voice_os_vs_ua · convicts
browserlayer
coherencecategory
What it catches
CreepJS: OS-specific TTS voices (Microsoft/Apple/espeak) betray a spoofed UA platform
Signals it reads
browser.voice_os_hint browser.ua_platform
How it fires
not_equal
Bypassed by 10
Frontier evaders that reach the detector uncaught (scored only suspicious, defeating every convicting tell) — this check is not one that stops them. The red-team frontier this detection still has to convict.