apply fix

src/devtools/client/inspector/computed/actions/index.ts

@@ -112,6 +112,7 @@ export async function createComputedProperties(
               stylesheet,
               stylesheetURL,
               overridden: !!property.overridden,
+              important: property.priority === "important",
             });
           }
         }

src/devtools/client/inspector/computed/components/MatchedSelector.tsx

@@ -31,6 +31,7 @@ export default function MatchedSelector(props: MatchedSelectorProps) {
             colorSwatchClassName="computed-colorswatch"
             fontFamilySpanClassName="computed-font-family"
             values={selector.parsedValue}
+            important={selector.important}
           />
         </div>
       </span>

src/devtools/client/inspector/computed/state/index.ts

@@ -12,6 +12,7 @@ export interface MatchedSelectorState {
   overridden: boolean;
   stylesheet: string;
   stylesheetURL: string;
+  important: boolean;
 }
 
 export interface ComputedState {

src/devtools/client/inspector/rules/components/DeclarationValue.tsx

@@ -11,11 +11,12 @@ interface DeclarationValueProps {
   colorSwatchClassName: string;
   fontFamilySpanClassName: string;
   values: (string | Record<string, string>)[];
+  important?: boolean;
 }
 
 class DeclarationValue extends React.PureComponent<DeclarationValueProps> {
   render() {
-    return this.props.values.map(v => {
+    const renderedValues = this.props.values.map(v => {
       if (typeof v === "string") {
         return v;
       }
@@ -46,6 +47,13 @@ class DeclarationValue extends React.PureComponent<DeclarationValueProps> {
 
       return value;
     });
+
+    return (
+      <React.Fragment>
+        {renderedValues}
+        {this.props.important && " !important"}
+      </React.Fragment>
+    );
   }
 }