RE: face cache referred to but not explained

[Drew Adams]

    > Can we at least get a description of what the face cache
    > _is_? (What it does? What it is for?)

    It's an obscure internal detail that is of no interest neither to
    users nor to Lisp programmers.... Why a cache is needed in this
    particular case and how it is managed, are issues that no one
    except redisplay hackers should care about.

Then why is it mentioned in the Elisp manual (node Font Selection)?

If it's mentioned, it should be described a bit; otherwise, let's pull it
out.