HyBrit Head is an hybrid amp model based on two famous British gears.
The PLS channel is actually an hybrid of the two (tweaked) channels (Normal and Treble) of the real thing. Both channels are actually processed and the mix of the two signals can be adjusted through the PLS MIX knob.
The other channel, MCJ, is also a tweaked version of the real thing. So, this amp simulator doesn’t represent anything specifically but it does have the character of the British amp.