Yes it's certainly the information that hasn't been disclosed by FIA, though not sure about the reason. It may be because of the same thing you quoted from "Autosport".
And only thing we know about jumpstart and tolerance is from the FIA statement that is in your provided link stating:
The jump start system judges whether a car has moved a pre-set (very small) distance between the point at which the last red light comes on and the point at which the lights go out.
That pre-set distance may possibly be the position of transponder relative to numerous wire aerials embedded in the track and pit lane. Source
Sporting and technical regulations also mention the transponder once.
36.13 Either of the penalties under Articles 38.3c) or d) will be imposed for a false start judged using an FIA supplied transponder which must be fitted to the car as specified.
where the referenced articles are
38.3 c) A drive-through penalty. The driver must enter the pit lane and re-join the race without stopping. d) A ten second stop-and-go time penalty. The driver must enter the pit lane, stop in his pit stop position for at least ten seconds and then re-join the race.
20.4 Transponders : All cars must be fitted with two timing transponders supplied by the officially appointed timekeepers. These transponders must be fitted in strict accordance with the instructions detailed in the Appendix to the Technical Regulations. Teams must use their best endeavours to ensure that the transponders are in working order at all times.
References: formula1.com, drivetribe, planetf1