Even though vendor-specific properties are guaranteed not to cause conflicts, it should be recognized that these extensions may also be subject to change at the vendor’s whim, as they don’t form part of the CSS specifications, even though they often mimic the proposed behavior of existing or forthcoming CSS properties. Thus, it is not recommended to use them in production code.

The rule raises an issue when one of the following prefixes is found:

This rule also raises an issue when one of the following experimental properties is found. A property is considered as experimental if it is not supported by IE/Edge 11+, Firefox 44+ and Chrome 48+.

accelerator additive-symbols alignment-baseline  #2
any-hover any-pointer aspect-ratio
background-blend-mode background-image-transform background-position-x
background-position-y baseline-shift bleed
block-progression block-size bookmark-label
bookmark-level bookmark-state border-block-end
border-block-end-color border-block-end-style border-block-end-width
border-block-start border-block-start-color border-block-start-style
border-block-start-width border-boundary border-inline-end
border-inline-end-color border-inline-end-style border-inline-end-width
border-inline-start border-inline-start-color border-inline-start-style
border-inline-start-width box-snap box-suppress
break-after  #2 break-before  #2 break-inside  #2
caret caret-color caret-shape
clip-rule  #2 color-gamut color-index
color-rendering column-count  #2 column-fill  #2
column-gap  #2 column-rule  #2 column-rule-color  #2
column-rule-style  #2 column-rule-width  #2 column-span  #2
column-width  #2  #3 columns  #2 content-zoom-chaining
content-zoom-limit content-zoom-limit-max content-zoom-limit-min
content-zoom-snap content-zoom-snap-points content-zoom-snap-type
content-zooming counter-set cue
cue-after cue-before device-aspect-ratio
device-height device-pixel-ratio  #2 device-width
dominant-baseline fallback filter
float-defer float-offset float-reference
flood-color  #2 flood-opacity  #2 flow-from
flow-into font-language-override font-size-adjust
font-synthesis font-variant-alternates font-variant-caps
font-variant-east-asian font-variant-numeric font-variant-position
footnote-display footnote-policy grid  #2
grid-area grid-auto-columns grid-auto-flow
grid-auto-rows grid-column grid-column-end
grid-column-gap grid-column-start grid-gap
grid-row grid-row-end grid-row-gap
grid-row-start grid-template grid-template-areas
grid-template-columns grid-template-rows hanging-punctuation
high-contrast high-contrast-adjust hover
hyphenate-character hyphenate-limit-chars  #2 hyphenate-limit-last
hyphenate-limit-lines  #2 hyphenate-limit-zone  #2 hyphens  #2
image-orientation image-rendering image-resolution
initial-letter initial-letter-align initial-letter-wrap
inline-size isolation justify-items
justify-self layout-flow layout-grid
layout-grid-char layout-grid-line layout-grid-mode
layout-grid-type lighting-color  #2 line-break
line-grid line-snap margin-block-end
margin-block-start margin-inline-end margin-inline-start
marker-side marker-start marks
mask mask-border mask-border-mode
mask-border-outset mask-border-repeat mask-border-slice
mask-border-source mask-border-width mask-clip
mask-composite mask-image mask-mode
mask-origin mask-position mask-repeat
mask-size mask-type max-block-size
max-device-pixel-ratio  #2 max-inline-size max-lines
max-zoom min-block-size min-device-pixel-ratio  #2
min-inline-size min-zoom mix-blend-mode
monochrome motion motion-offset
motion-path motion-rotation nav-down
nav-left nav-right nav-up
negative object-fit  #2 object-position  #2
offset-after offset-anchor offset-before
offset-block-end offset-block-start offset-distance
offset-end offset-inline-end offset-inline-start
offset-origin offset-path offset-rotation
offset-start orientation  #2 outline-offset
overflow-block overflow-inline overflow-style
pad padding-block-end padding-block-start
padding-inline-end padding-inline-start page
page-break-after pause pause-after
pause-before place-content place-items
place-self pointer prefix
range region-fragment resize
resolution rest rest-after
rest-before ruby-align ruby-merge
ruby-position scan scripting
scroll-behavior scroll-chaining scroll-limit
scroll-limit-x-max scroll-limit-x-min scroll-limit-y-max
scroll-limit-y-min scroll-rails scroll-snap-align
scroll-snap-margin scroll-snap-margin-block scroll-snap-margin-block-end
scroll-snap-margin-block-start scroll-snap-margin-bottom scroll-snap-margin-inline
scroll-snap-margin-inline-end scroll-snap-margin-inline-start scroll-snap-margin-left
scroll-snap-margin-right scroll-snap-margin-top scroll-snap-padding
scroll-snap-padding-block scroll-snap-padding-block-end scroll-snap-padding-block-start
scroll-snap-padding-bottom scroll-snap-padding-inline scroll-snap-padding-inline-end
scroll-snap-padding-inline-start scroll-snap-padding-left scroll-snap-padding-right
scroll-snap-padding-top scroll-snap-points-x scroll-snap-points-y
scroll-snap-stop scroll-snap-type scroll-snap-x
scroll-snap-y scroll-translation scrollbar-3dlight-color
scrollbar-darkshadow-color scrollbar-highlight-color scrollbar-shadow-color
scrollbar-track-color shape shape-image-threshold
shape-inside shape-margin shape-outside
size speak speak-as  #2
string-set  #2 suffix symbols
system tab-size text-align-all
text-align-last text-auto-space text-combine-horizontal
text-combine-upright text-decoration-color text-decoration-line
text-decoration-skip text-decoration-style text-emphasis
text-emphasis-color text-emphasis-position text-emphasis-style
text-height text-justify text-orientation
text-size-adjust text-space-collapse text-space-trim
text-spacing text-underline-position text-wrap
touch-action transform-box update
user-select  #2 user-zoom viewport-fit
voice-balance voice-duration voice-family
voice-pitch voice-range voice-rate
voice-stress voice-volume will-change
wrap-after wrap-before wrap-flow
wrap-inside wrap-margin wrap-through
writing-mode zoom

Noncompliant Code Example

.mybox {
  -moz-border-radius: 5px;  /* Noncompliant: vendor-prefixed property */
  pause: 3s;  /* Noncompliant: experimental property */
}

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