I wouldn't say well-written (see other comments too)

Two quite serious things:
The physical memory bar (on the right) suggests that 1GB of
kernel-mapped virtual memory covers *first* 1GB of physical
memory. This is not true. 1GB total, yes, but
that doesn't have to be the first 1GB of physical memory.
This 1GB can be spread among physical pages located *anywhere*
in the physical memory.

Similarly, sentence: "The kernel virtual area (3 - 4 GB
address space) maps to the first 1 GB of physical RAM."
is just false.

Cheers!