r <- residuals(x)                                # <---  r contains residuals

...

if (any(show[2L:6L])) {
    s <- if (inherits(x, "rlm"))
        x$s
    else if (isGlm)
        sqrt(summary(x)$dispersion)
    else sqrt(deviance(x)/df.residual(x))        #<---- value of s
    hii <- lm.influence(x, do.coef = FALSE)$hat  #<---- value of hii

...

    r.w <- if (is.null(w))
        r                                        #<-- r.w  for unweighted regression
    else sqrt(w) * r
    rs <- dropInf(r.w/(s * sqrt(1 - hii)), hii)  # <-- std. residual in plots