Seems like a ballsed up version with missing resistors that will be become unstable at full treble.
** And like most stuff on hobby web sites it is bunkum.
The "Baxandall" tone control design was published in Wireless World in 952 - it used valves. The network is different to the one in the link above and produces variable turnover at both the high and low ends of the range.
formatting link
... Phil