The fact that there is no newer bug ticket for it in 12 years shows is this a purely academic feature nobody wanted.
And why should they? Most Blu-ray players support the old format (SRT); converting it to PGS gains almost none of the upsides of the newer format (screen placement).
And why should they? Most Blu-ray players support the old format (SRT); converting it to PGS gains almost none of the upsides of the newer format (screen placement).