Why should we buffer reset line?
It's actually used as a level-shifter. It's converting the 3V PCH_PLTRST# to a 1V open-drain signal. In many cases, the reset input of a CPU can also act as an open-drain output, so the CPU can reset the surrounding system. If that's the case, you shouldn't drive the reset pin using a push-pull signal, otherwise it will create a short circuit when the buffer drives high and the processor pulls low.
-
R32 is the pull-up, see above. Not sure about the purpose of R34 though.
The special resistor symbol stands for a bridge made by solder or directly on copper on the PCB, but still offers the possibility to remove the bridge and install a component. The @ near means, that no component is installed.