It might be nice to have something like:
(defsubst buffer-internal-p (buf)
(eq (aref (buffer-name buf) 0) ?\s))
Yup. I also see this in the "(emacs) Undo" Info node:
Some specialized buffers do not make undo records. Buffers whose
names start with spaces never do; these buffers are used internally by
Emacs to hold text that users don’t normally look at or edit.
But I cannot find the code that implements that.
It would be nice to have these places to use the same defsubst.
Btw I confirm the fix. Thanks!