diff --git a/collects/plot/common/parameters.rkt b/collects/plot/common/parameters.rkt
index 45d7c15377..2b0387f854 100644
--- a/collects/plot/common/parameters.rkt
+++ b/collects/plot/common/parameters.rkt
@@ -20,8 +20,7 @@
 (defparam plot-height exact-positive-integer? 400)
 (defparam plot-new-window? boolean? #f)
 (defparam plot-jpeg-quality (integer-in 0 100) 100)
-(defparam plot-ps-interactive? boolean? #f)
-(defparam plot-pdf-interactive? boolean? #f)
+(defparam plot-ps/pdf-interactive? boolean? #f)
 
 ;; General appearance
 
@@ -46,6 +45,12 @@
 (defparam plot-y-label (or/c string? #f) "y axis")
 (defparam plot-z-label (or/c string? #f) #f)
 
+(defparam plot-animating? boolean? #f)
+
+(defproc (animated-samples [samples (and/c exact-integer? (>=/c 2))]) (and/c exact-integer? (>=/c 2))
+  (cond [(plot-animating?)  (max 2 (ceiling (* 1/4 samples)))]
+        [else  samples]))
+
 ;; Lines
 
 (defparam line-samples (and/c exact-integer? (>=/c 2)) 500)
@@ -148,18 +153,12 @@
 ;; General appearance
 
 (defparam plot3d-samples (and/c exact-integer? (>=/c 2)) 41)
-(defparam plot3d-animating? boolean? #f)
 (defparam plot3d-angle real? 30)
 (defparam plot3d-altitude real? 60)
-(defparam plot3d-ambient-light-value (real-in 0 1) 2/3)
+(defparam plot3d-ambient-light (real-in 0 1) 2/3)
 (defparam plot3d-diffuse-light? boolean? #t)
 (defparam plot3d-specular-light? boolean? #t)
 
-(defproc (samples/animating? [samples (and/c exact-integer? (>=/c 2))]
-                             ) (and/c exact-integer? (>=/c 2))
-  (cond [(plot3d-animating?)  (max 2 (ceiling (* 1/4 samples)))]
-        [else  samples]))
-
 ;; Surfaces
 
 (defparam surface-color plot-color/c 0)
diff --git a/collects/plot/deprecated.rkt b/collects/plot/deprecated.rkt
index 4f050d4c84..5099f52abb 100644
--- a/collects/plot/deprecated.rkt
+++ b/collects/plot/deprecated.rkt
@@ -11,18 +11,9 @@
          "plot3d/surface.rkt"
          "plot3d/renderer.rkt"
          "utils.rkt"
-         "deprecated/renderers.rkt"
-         ;; Curve fitting
-         "deprecated/fit.rkt"
-         ;; Miscellaneous
-         "deprecated/math.rkt")
+         "deprecated/renderers.rkt")
 
-(provide mix line contour shade surface
-         ;; Curve fitting
-         (rename-out [fit-int fit])
-         (struct-out fit-result)
-         ;; Miscellaneous
-         make-vec derivative gradient)
+(provide mix line contour shade surface)
 
 (define (mix . renderers)
   (deprecation-warning "mix" "list")
diff --git a/collects/plot/plot2d/area.rkt b/collects/plot/plot2d/area.rkt
index 713c3baa5a..8ed1256b0c 100644
--- a/collects/plot/plot2d/area.rkt
+++ b/collects/plot/plot2d/area.rkt
@@ -246,8 +246,8 @@
     
     (define/public (start-renderer rx-min rx-max ry-min ry-max)
       (reset-drawing-params)
-      (set-clipping-rect (vector (- area-x-min (plot-line-width))
-                                 (- area-y-min (plot-line-width)))
+      (set-clipping-rect (vector (+ 1/2 (- area-x-min (plot-line-width)))
+                                 (+ 1/2 (- area-y-min (plot-line-width))))
                          (vector (+ area-x-max (plot-line-width))
                                  (+ area-y-max (plot-line-width))))
       (clip-to-bounds rx-min rx-max ry-min ry-max))
diff --git a/collects/plot/plot2d/plot.rkt b/collects/plot/plot2d/plot.rkt
index 122127eed3..5689886c57 100644
--- a/collects/plot/plot2d/plot.rkt
+++ b/collects/plot/plot2d/plot.rkt
@@ -131,6 +131,8 @@
   (define tick-skip (plot-tick-skip))
   (define x-transform (plot-x-transform))
   (define y-transform (plot-y-transform))
+  (define z-transform (plot-z-transform))
+  (define animating? (plot-animating?))
   
   (dc (λ (dc x y)
         (parameterize ([plot-foreground        foreground]
@@ -144,7 +146,9 @@
                        [plot-tick-size         tick-size]
                        [plot-tick-skip         tick-skip]
                        [plot-x-transform       x-transform]
-                       [plot-y-transform       y-transform])
+                       [plot-y-transform       y-transform]
+                       [plot-z-transform       z-transform]
+                       [plot-animating?        animating?])
           (plot/dc renderer-tree dc x y width height
                    #:x-min x-min #:x-max x-max #:y-min y-min #:y-max y-max
                    #:title title #:x-label x-label #:y-label y-label #:legend-anchor legend-anchor)))
@@ -211,10 +215,10 @@
      (define dc
        (case real-kind
          [(ps)  (new post-script-dc%
-                     [interactive (plot-ps-interactive?)] [parent #f] [use-paper-bbox #f] [as-eps #t]
-                     [width width] [height height] [output output])]
+                     [interactive (plot-ps/pdf-interactive?)] [parent #f] [use-paper-bbox #f]
+                     [as-eps #t] [width width] [height height] [output output])]
          [(pdf)  (new pdf-dc%
-                      [interactive (plot-pdf-interactive?)] [parent #f] [use-paper-bbox #f]
+                      [interactive (plot-ps/pdf-interactive?)] [parent #f] [use-paper-bbox #f]
                       [width width] [height height] [output output])]
          [(svg)  (new svg-dc%
                       [width width] [height height] [output output] [exists 'truncate/replace])]))
diff --git a/collects/plot/plot3d/area.rkt b/collects/plot/plot3d/area.rkt
index 9803775e26..c000c4c0e7 100644
--- a/collects/plot/plot3d/area.rkt
+++ b/collects/plot/plot3d/area.rkt
@@ -467,7 +467,7 @@
                              (* 32 (expt (if (cos-angle . > . 0) cos-angle 0.0) 10))]
                             [else  0.0]))
          ; ambient lighting
-         (define amb (plot3d-ambient-light-value))
+         (define amb (plot3d-ambient-light))
          ; put it all together
          (values (+ amb (* (- 1 amb) diff)) spec)]))
     
diff --git a/collects/plot/plot3d/contour.rkt b/collects/plot/plot3d/contour.rkt
index 5c8bcee125..05ed7646e5 100644
--- a/collects/plot/plot3d/contour.rkt
+++ b/collects/plot/plot3d/contour.rkt
@@ -21,8 +21,8 @@
 
 (define ((contours3d-render-proc f levels samples colors widths styles alphas label) area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))
-  (match-define (list xs ys zss) (f x-min x-max (samples/animating? samples)
-                                    y-min y-max (samples/animating? samples)))
+  (match-define (list xs ys zss) (f x-min x-max (animated-samples samples)
+                                    y-min y-max (animated-samples samples)))
   (define zs
     (cond [(list? levels)      levels]
           [(eq? levels 'auto)  (auto-contour-zs z-min z-max)]
@@ -91,8 +91,8 @@
           contour-colors contour-widths contour-styles alphas label)
          area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))  
-  (match-define (list xs ys zss) (f x-min x-max (samples/animating? samples)
-                                    y-min y-max (samples/animating? samples)))
+  (match-define (list xs ys zss) (f x-min x-max (animated-samples samples)
+                                    y-min y-max (animated-samples samples)))
   
   (define contour-zs
     (cond [(list? levels)      levels]
diff --git a/collects/plot/plot3d/isosurface.rkt b/collects/plot/plot3d/isosurface.rkt
index 923b1988ad..e8b745fd73 100644
--- a/collects/plot/plot3d/isosurface.rkt
+++ b/collects/plot/plot3d/isosurface.rkt
@@ -25,9 +25,9 @@
          area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))
   (match-define (list xs ys zs dsss)
-    (f x-min x-max (samples/animating? samples)
-       y-min y-max (samples/animating? samples)
-       z-min z-max (samples/animating? samples)))
+    (f x-min x-max (animated-samples samples)
+       y-min y-max (animated-samples samples)
+       z-min z-max (animated-samples samples)))
   
   (send area put-alpha alpha)
   (send area put-brush color 'solid)
@@ -98,9 +98,9 @@
          area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))
   (match-define (list xs ys zs dsss)
-    (f x-min x-max (samples/animating? samples)
-       y-min y-max (samples/animating? samples)
-       z-min z-max (samples/animating? samples)))
+    (f x-min x-max (animated-samples samples)
+       y-min y-max (animated-samples samples)
+       z-min z-max (animated-samples samples)))
   
   (define-values (fd-min fd-max)
     (let ([regular-ds  (filter regular? (3d-sample->list dsss))])
@@ -189,9 +189,9 @@
 (define ((polar3d-render-proc f g samples color line-color line-width line-style alpha label) area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))
   (match-define (list xs ys zs dsss)
-    (g x-min x-max (samples/animating? samples)
-       y-min y-max (samples/animating? samples)
-       z-min z-max (samples/animating? samples)))
+    (g x-min x-max (animated-samples samples)
+       y-min y-max (animated-samples samples)
+       z-min z-max (animated-samples samples)))
   
   (send area put-alpha alpha)
   (send area put-brush color 'solid)
diff --git a/collects/plot/plot3d/line.rkt b/collects/plot/plot3d/line.rkt
index 37d7b05beb..e7ced21fc5 100644
--- a/collects/plot/plot3d/line.rkt
+++ b/collects/plot/plot3d/line.rkt
@@ -65,5 +65,5 @@
           [#:alpha alpha (real-in 0 1) (line-alpha)]
           [#:label label (or/c string? #f) #f]
           ) renderer3d?
-  (lines3d-renderer (λ () (sample-parametric f t-min t-max (samples/animating? samples)))
+  (lines3d-renderer (λ () (sample-parametric f t-min t-max (animated-samples samples)))
                     x-min x-max y-min y-max z-min z-max color width style alpha label))
diff --git a/collects/plot/plot3d/plot.rkt b/collects/plot/plot3d/plot.rkt
index 1b0ffb3088..2df82378ea 100644
--- a/collects/plot/plot3d/plot.rkt
+++ b/collects/plot/plot3d/plot.rkt
@@ -93,11 +93,11 @@
         (send area end-plot)
         
         (when (and (not (empty? legend-entries))
-                   (or (not (plot3d-animating?))
+                   (or (not (plot-animating?))
                        (not (equal? (plot-legend-anchor) 'center))))
           (send area put-legend legend-entries))
         
-        (when (plot3d-animating?) (send area put-angles))
+        (when (plot-animating?) (send area put-angles))
         
         (send area restore-drawing-params)))))
 
@@ -154,31 +154,31 @@
   (define x-transform (plot-x-transform))
   (define y-transform (plot-y-transform))
   (define z-transform (plot-z-transform))
+  (define animating? (plot-animating?))
   (define samples (plot3d-samples))
-  (define animating? (plot3d-animating?))
-  (define ambient-light-value (plot3d-ambient-light-value))
+  (define ambient-light (plot3d-ambient-light))
   (define diffuse-light? (plot3d-diffuse-light?))
   (define specular-light? (plot3d-specular-light?))
   
   (dc (λ (dc x y)
-        (parameterize ([plot-foreground             foreground]
-                       [plot-background             background]
-                       [plot-foreground-alpha  foreground-alpha]
-                       [plot-background-alpha  background-alpha]
-                       [plot-font-size              font-size]
-                       [plot-font-family            font-family]
-                       [plot-line-width             line-width]
-                       [plot-legend-box-alpha       legend-box-alpha]
-                       [plot-tick-size              tick-size]
-                       [plot-tick-skip              tick-skip]
-                       [plot-x-transform            x-transform]
-                       [plot-y-transform            y-transform]
-                       [plot-z-transform            z-transform]
-                       [plot3d-samples              samples]
-                       [plot3d-animating?           animating?]
-                       [plot3d-ambient-light-value  ambient-light-value]
-                       [plot3d-diffuse-light?       diffuse-light?]
-                       [plot3d-specular-light?      specular-light?])
+        (parameterize ([plot-foreground         foreground]
+                       [plot-background         background]
+                       [plot-foreground-alpha   foreground-alpha]
+                       [plot-background-alpha   background-alpha]
+                       [plot-font-size          font-size]
+                       [plot-font-family        font-family]
+                       [plot-line-width         line-width]
+                       [plot-legend-box-alpha   legend-box-alpha]
+                       [plot-tick-size          tick-size]
+                       [plot-tick-skip          tick-skip]
+                       [plot-x-transform        x-transform]
+                       [plot-y-transform        y-transform]
+                       [plot-z-transform        z-transform]
+                       [plot-animating?         animating?]
+                       [plot3d-samples          samples]
+                       [plot3d-ambient-light    ambient-light]
+                       [plot3d-diffuse-light?   diffuse-light?]
+                       [plot3d-specular-light?  specular-light?])
           (plot3d/dc
            renderer-tree dc x y width height
            #:x-min x-min #:x-max x-max #:y-min y-min #:y-max y-max #:z-min z-min #:z-max z-max
@@ -203,7 +203,7 @@
                       ) (is-a?/c image-snip%)
   (make-3d-plot-snip
    (λ (angle altitude anim?)
-     (parameterize ([plot3d-animating?  (if anim? #t (plot3d-animating?))])
+     (parameterize ([plot-animating?  (if anim? #t (plot-animating?))])
        (plot3d-bitmap
         renderer-tree
         #:x-min x-min #:x-max x-max #:y-min y-min #:y-max y-max #:z-min z-min #:z-max z-max
@@ -264,10 +264,10 @@
      (define dc
        (case real-kind
          [(ps)  (new post-script-dc%
-                     [interactive (plot-ps-interactive?)] [parent #f] [use-paper-bbox #f] [as-eps #t]
-                     [width width] [height height] [output output])]
+                     [interactive (plot-ps/pdf-interactive?)] [parent #f] [use-paper-bbox #f]
+                     [as-eps #t] [width width] [height height] [output output])]
          [(pdf)  (new pdf-dc%
-                      [interactive (plot-pdf-interactive?)] [parent #f] [use-paper-bbox #f]
+                      [interactive (plot-ps/pdf-interactive?)] [parent #f] [use-paper-bbox #f]
                       [width width] [height height] [output output])]
          [(svg)  (new svg-dc%
                       [width width] [height height] [output output] [exists 'truncate/replace])]))
diff --git a/collects/plot/plot3d/surface.rkt b/collects/plot/plot3d/surface.rkt
index 5e6943ad94..e858f586d0 100644
--- a/collects/plot/plot3d/surface.rkt
+++ b/collects/plot/plot3d/surface.rkt
@@ -23,8 +23,8 @@
 (define ((surface3d-render-proc f samples color style line-color line-width line-style alpha label)
          area)
   (define-values (x-min x-max y-min y-max z-min z-max) (send area get-bounds))
-  (match-define (list xs ys zss) (f x-min x-max (samples/animating? samples)
-                                    y-min y-max (samples/animating? samples)))
+  (match-define (list xs ys zss) (f x-min x-max (animated-samples samples)
+                                    y-min y-max (animated-samples samples)))
   
   (send area put-alpha alpha)
   (send area put-brush color style)
diff --git a/collects/plot/scribblings/compat.scrbl b/collects/plot/scribblings/compat.scrbl
index 0c37b0686e..8ec712b9da 100644
--- a/collects/plot/scribblings/compat.scrbl
+++ b/collects/plot/scribblings/compat.scrbl
@@ -129,8 +129,17 @@ Returns @racket[#t] if @racket[v] is one of the following symbols,
 
 @section[#:tag "curve-fit"]{Curve Fitting}
 
-The @racketmodname[plot] library uses a non-linear, least-squares fit
-algorithm to fit parameterized functions to given data.
+@define[fit-warning]{
+@para{
+@bold{Do not use the @(racket fit) function. It is going to be removed in Racket 5.2.1.}
+It relies on old C code that nobody understands or is willing to maintain, and that is also slightly crashy.
+}}
+
+@fit-warning
+
+Quite independent of plotting, and for reasons lost in the sands of time,
+the @racketmodname[plot] library provides a non-linear, least-squares
+fit algorithm to fit parameterized functions to given data.
 The code that implements the algorithm is public
 domain, and is used by the @tt{gnuplot} package.
 
@@ -204,6 +213,8 @@ A more realistic example can be found in
                           (list-of (vector/c real? real? real? real?)))])
          fit-result?]{
 
+@fit-warning
+                       
 Attempts to fit a @defterm{fittable function} to the data that is
 given. The @racket[guess-list] should be a set of arguments and
 values. The more accurate your initial guesses are, the more likely
diff --git a/collects/plot/scribblings/params.scrbl b/collects/plot/scribblings/params.scrbl
index 687f4e364e..3aaa1ce164 100644
--- a/collects/plot/scribblings/params.scrbl
+++ b/collects/plot/scribblings/params.scrbl
@@ -27,12 +27,8 @@ before using @(racket plot) or @(racket plot3d).}
 The quality of JPEG images written by @(racket plot-file) and @(racket plot3d-file). See @(method bitmap% save-file).
 }
 
-@doc-apply[plot-ps-interactive?]{
-If @(racket #t), @(racket plot-file) and @(racket plot3d-file) open a dialog when writing PostScript files. See @(racket post-script-dc%).
-}
-
-@doc-apply[plot-pdf-interactive?]{
-If @(racket #t), @(racket plot-file) and @(racket plot3d-file) open a dialog when writing PDF files. See @(racket pdf-dc%).
+@doc-apply[plot-ps/pdf-interactive?]{
+If @(racket #t), @(racket plot-file) and @(racket plot3d-file) open a dialog when writing PostScript or PDF files. See @(racket post-script-dc%) and @(racket pdf-dc%).
 }
 
 @section{Axis Transforms}
@@ -96,6 +92,10 @@ See @(racket ->pen-color) and @(racket ->brush-color) for details on how PLoT in
 @doc-apply[plot-z-label]{The title and axis labels. A @(racket #f) value means the label is not drawn and takes no space. A @(racket "") value effectively means the label is not drawn, but it takes space.
 }
 
+@doc-apply[plot-animating?]{
+When @(racket #t), certain renderers draw simplified plots to speed up drawing. PLoT sets it to @(racket #t), for example, when a user is clicking and dragging a 3D plot to rotate it.
+}
+
 @section{Lines}
 
 @doc-apply[line-samples]
@@ -189,10 +189,9 @@ These parameters do not control the @italic{typical} appearance of plots. Instea
 @section{3D General Appearance}
 
 @doc-apply[plot3d-samples]
-@doc-apply[plot3d-animating?]
 @doc-apply[plot3d-angle]
 @doc-apply[plot3d-altitude]
-@doc-apply[plot3d-ambient-light-value]
+@doc-apply[plot3d-ambient-light]
 @doc-apply[plot3d-diffuse-light?]
 @doc-apply[plot3d-specular-light?]
 
diff --git a/collects/plot/scribblings/plot2d.scrbl b/collects/plot/scribblings/plot2d.scrbl
index 6e0dee80b0..9893030dc2 100644
--- a/collects/plot/scribblings/plot2d.scrbl
+++ b/collects/plot/scribblings/plot2d.scrbl
@@ -62,7 +62,7 @@ Plot to different backends. Each of these procedures has the same keyword argume
 
 Use @(racket plot-file) to save a plot to a file.
 When creating a JPEG file, the parameter @(racket plot-jpeg-quality) determines its quality.
-When creating a PostScript or PDF file, the parameters @(racket plot-ps-interactive?) and @(racket plot-pdf-interactive?) determine whether the user is given a dialog for setting printing parameters.
+When creating a PostScript or PDF file, the parameter @(racket plot-ps/pdf-interactive?) determines whether the user is given a dialog for setting printing parameters.
 (See @(racket post-script-dc%) and @(racket pdf-dc%).)
 When @(racket kind) is @(racket 'auto), @(racket plot-file) tries to determine the kind of file to write from the file name extension.
 
diff --git a/collects/plot/tests/compat-tests.rkt b/collects/plot/tests/compat-tests.rkt
index dcf2573f0f..22caf316d1 100644
--- a/collects/plot/tests/compat-tests.rkt
+++ b/collects/plot/tests/compat-tests.rkt
@@ -1,7 +1,7 @@
 #reader(lib"read.ss""wxme")WXME0108 ## 
 #|
    This file uses the GRacket editor format.
-   Open this file in DrRacket version 5.1.3.11 or later to read it.
+   Open this file in DrRacket version 5.2.0.1 or later to read it.
 
    Most likely, it was created by saving a program in DrRacket,
    and it probably contains a program with non-text elements
@@ -446,7 +446,7 @@
 255 255 -1 -1 43 1 #"\0"
 0 -1 1 #"\0"
 1.0 0 -1 -1 -1 -1 -1 -1 0 0 0 0 1 0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 0 255
-255 255 -1 -1           0 1595 0 26 3 12 #"#lang racket"
+255 255 -1 -1           0 1589 0 26 3 12 #"#lang racket"
 0 0 4 29 1 #"\n"
 0 0 4 29 1 #"\n"
 0 0 17 3 1 #"#"
@@ -494,6 +494,18 @@
 0 0 4 29 1 #"\n"
 0 0 4 29 1 #"\n"
 0 0 22 3 1 #"("
+0 0 14 3 7 #"require"
+0 0 4 3 1 #" "
+0 0 22 3 1 #"("
+0 0 14 3 7 #"only-in"
+0 0 4 3 1 #" "
+0 0 14 3 11 #"plot/compat"
+0 0 4 3 1 #" "
+0 0 14 3 8 #"gradient"
+0 0 22 3 2 #"))"
+0 0 4 29 1 #"\n"
+0 0 4 29 1 #"\n"
+0 0 22 3 1 #"("
 0 0 15 3 6 #"define"
 0 0 4 3 1 #" "
 0 0 22 3 1 #"("
@@ -542,8 +554,7 @@
 0 0 4 3 1 #" "
 0 0 19 3 1 #"\""
 0 0 19 3 3 #"The"
-0 0 19 3 1 #" "
-0 0 19 3 37 #"old plot library produced this plot:\""
+0 0 19 3 38 #" old plot library produced this plot:\""
 0 0 22 3 1 #")"
 0 0 4 29 1 #"\n"
 0 0 4 3 2 #"  "
@@ -742,21 +753,6 @@
 0 0 22 3 2 #"))"
 0 0 4 29 1 #"\n"
 0 0 4 3 2 #"  "
-0 0 22 3 1 #"("
-0 0 15 3 6 #"define"
-0 0 4 3 1 #" "
-0 0 14 3 8 #"gradient"
-0 0 4 3 1 #" "
-0 0 22 3 1 #"("
-0 0 14 3 15 #"dynamic-require"
-0 0 4 3 1 #" "
-0 0 14 3 11 #"module-path"
-0 0 4 3 1 #" "
-0 0 20 3 1 #"'"
-0 0 14 3 8 #"gradient"
-0 0 22 3 2 #"))"
-0 0 4 29 1 #"\n"
-0 0 4 3 2 #"  "
 0 0 4 29 1 #"\n"
 0 0 4 3 2 #"  "
 0 0 17 3 71
@@ -14292,8 +14288,7 @@
 0 0 4 3 1 #" "
 0 0 19 3 1 #"\""
 0 0 19 3 7 #"Testing"
-0 0 19 3 1 #" "
-0 0 19 3 18 #"plot's #:out-file\""
+0 0 19 3 19 #" plot's #:out-file\""
 0 0 22 3 1 #")"
 0 0 4 29 1 #"\n"
 0 0 4 3 2 #"  "
@@ -14349,8 +14344,7 @@
 0 0 4 3 1 #" "
 0 0 19 3 1 #"\""
 0 0 19 3 7 #"Testing"
-0 0 19 3 1 #" "
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diff --git a/collects/plot/tests/fit-test-1.rkt b/collects/plot/tests/fit-test-1.rkt
index 132e285e8e..9e3f47ed72 100644
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index fd8b256223..bad31fed8e 100644
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