diff --git a/docs/contributing.md b/docs/contributing.md
index 0f9024009e7349..37de1e33cac263 100644
--- a/docs/contributing.md
+++ b/docs/contributing.md
@@ -80,18 +80,18 @@ If the feature you're interested in is an API, CSS or JavaScript feature, you ca
 
 Many browsers within BCD can be derived from other browsers given they share the same engine, for example Opera derives from Chrome, and Firefox Android derives from Firefox. To help cut down time working on copying values between browsers, a mirroring script is provided. You can run `npm run mirror <browser> <feature_or_file> [--source=""] [--modify=""]` to automatically copy values.
 
-The <browser> argument is the destination browser that values will be copied to. The script automatically determines what browser to copy from based upon the destination (see table below), but manual specification is possible through the `--source=""` argument.
-
-| Destination      | Default Source |
-| ---------------- | -------------- |
-| Chrome Android   | Chrome         |
-| Edge             | Chrome         |
-| Firefox Android  | Firefox        |
-| Opera            | Chrome         |
-| Opera Android    | Chrome Android |
-| Safari iOS       | Safari         |
-| Samsung Internet | Chrome Android |
-| WebView          | Chrome Android |
+The <browser> argument is the destination browser that values will be copied to. The script automatically determines what browser to copy from based upon the destination (see table below), but manual specification is possible through the `--source=""` argument. (Mirroring data for Edge ignores this argument.)
+
+| Destination      | Default Source             |
+| ---------------- | -------------------------- |
+| Chrome Android   | Chrome                     |
+| Edge             | Chrome + Internet Explorer |
+| Firefox Android  | Firefox                    |
+| Opera            | Chrome                     |
+| Opera Android    | Chrome Android             |
+| Safari iOS       | Safari                     |
+| Samsung Internet | Chrome Android             |
+| WebView          | Chrome Android             |
 
 The <feature_or_filename> argument is either the identifier of the feature to update (i.e. `css.at-rules.namespace`), a filename (`javascript/operators/arithmetic.json`), or an entire folder (`api`).
 
diff --git a/scripts/mirror.js b/scripts/mirror.js
index b39d1ff407189a..7febadb005feb9 100644
--- a/scripts/mirror.js
+++ b/scripts/mirror.js
@@ -160,9 +160,7 @@ const combineNotes = (notes1, notes2) => {
     }
   }
 
-  newNotes = newNotes.filter((item, pos) => {
-    newNotes.indexOf(item) == pos;
-  });
+  newNotes = newNotes.filter((item, pos) => newNotes.indexOf(item) == pos);
 
   if (newNotes.length == 0) {
     return null;
@@ -209,6 +207,79 @@ const copyStatement = (data) => {
   return newData;
 };
 
+/**
+ * @param {...SupportStatement} data
+ * @returns {SupportStatement}
+ */
+const combineStatements = (...data) => {
+  const ignored_keys = ['version_added', 'notes'];
+
+  let flattenedData = data.flat(2);
+  let sections = {};
+  let newData = [];
+
+  for (const d of flattenedData) {
+    let key = Object.keys(d)
+      .filter((k) => !ignored_keys.includes(k))
+      .join('');
+    if (!(key in sections)) sections[key] = [];
+    sections[key].push(d);
+  }
+
+  for (const k of Object.keys(sections)) {
+    let currentStatement = sections[k][0];
+
+    if (sections[k].length == 1) {
+      newData.push(currentStatement);
+      continue;
+    }
+
+    for (const i in sections[k]) {
+      if (i === 0) continue;
+      let newStatement = sections[k][i];
+
+      let currentVA = currentStatement.version_added;
+      let newVA = newStatement.version_added;
+
+      if (newVA === false) {
+        // Ignore statements with version_added being false
+        continue;
+      } else if (typeof newVA === 'string') {
+        if (
+          typeof currentVA !== 'string' ||
+          compareVersions.compare(
+            currentVA.replace('≤', ''),
+            newVA.replace('≤', ''),
+            '>',
+          )
+        ) {
+          currentStatement.version_added = newVA;
+        }
+      }
+
+      let newNotes = combineNotes(currentStatement.notes, newStatement.notes);
+      if (newNotes) currentStatement.notes = newNotes;
+    }
+
+    if ('notes' in currentStatement && !currentStatement.notes)
+      delete currentStatement.notes;
+    newData.push(currentStatement);
+  }
+
+  if (newData.length === 1) return newData[0];
+
+  // Remove duplicate statements and statements that are only version_added = false
+  newData = newData
+    .filter((item, pos) => newData.indexOf(item) == pos)
+    .filter((item) => item.version_added);
+
+  return newData.length === 0
+    ? { version_added: false }
+    : newData.length === 1
+    ? newData[0]
+    : newData;
+};
+
 /**
  * @param {SupportStatement} originalData
  * @param {SupportStatement} sourceData
@@ -240,74 +311,120 @@ const bumpChromeAndroid = (originalData, sourceData) => {
 };
 
 /**
- * @param {SupportStatement} originalData
  * @param {SupportStatement} sourceData
- * @param {string} source
  * @returns {SupportStatement}
  */
-const bumpEdge = (originalData, sourceData, source) => {
-  let newData = {};
+const bumpEdgeFromIE = (sourceData) => {
+  let newData = copyStatement(sourceData);
 
-  if (source == 'ie') {
-    if (sourceData.version_removed && sourceData.version_removed !== null) {
-      newData.version_added = false;
-    } else if (sourceData.version_added !== null) {
-      newData.version_added = sourceData.version_added ? '12' : null;
-    }
+  if (sourceData.version_removed || sourceData.version_added === false) {
+    newData.version_added = false;
+  } else if (sourceData.version_added) {
+    newData.version_added = '12';
+  }
 
-    if (sourceData.notes) {
-      newData.notes = updateNotes(
-        sourceData.notes,
-        /Internet Explorer/g,
-        'Edge',
-      );
-    }
-  } else if (source == 'chrome') {
-    newData = originalData == undefined ? sourceData : originalData;
+  let newNotes = updateNotes(sourceData.notes, /Internet Explorer/g, 'Edge');
+  if (newNotes) newData.notes = newNotes;
 
-    let chromeFalse =
-      sourceData.version_added === false ||
-      sourceData.version_removed !== undefined;
-    let chromeNull = sourceData.version_added === null;
+  return newData;
+};
 
-    if (originalData === undefined) {
-      newData.version_added = chromeFalse ? false : chromeNull ? null : '≤79';
-    } else {
-      if (!chromeFalse && !chromeNull) {
-        if (originalData.version_added == true) {
-          newData.version_added = '≤18';
-        } else {
-          if (
-            sourceData.version_added == true ||
-            Number(sourceData.version_added) <= 79
-          ) {
-            if (originalData.version_added == false) {
-              newData.version_added = '79';
-            } else if (originalData.version_added == null) {
-              newData.version_added = '≤79';
-            }
-          } else {
-            newData.version_added = sourceData.version_added;
-          }
-        }
-      } else if (chromeFalse) {
-        if (originalData.version_added && !originalData.version_removed) {
-          newData.version_removed = '79';
-        }
+/**
+ * @param {SupportStatement} sourceData
+ * @param {SupportStatement} originalData
+ * @returns {SupportStatement}
+ */
+const bumpEdgeFromChrome = (sourceData, originalData) => {
+  let newData = copyStatement(sourceData);
+
+  let chromeFalse =
+    sourceData.version_removed || sourceData.version_added === false;
+  let chromeNull = sourceData.version_added === null;
+
+  if (chromeFalse) {
+    if (
+      typeof sourceData.version_removed === 'string' &&
+      compareVersions.compare(sourceData.version_removed, '79', '<=')
+    ) {
+      // If this feature was removed before Chrome 79, it's not present in Edge
+      return { version_added: false };
+    }
+
+    if (
+      typeof sourceData.version_added === 'string' &&
+      compareVersions.compare(sourceData.version_added, '79', '<=')
+    ) {
+      // If the feature was added before Chrome 79 but removed afterwards
+      if (typeof originalData.version_added == 'string') {
+        newData.version_added = originalData.version_added;
+      } else {
+        newData.version_added = '79';
       }
     }
+    if (originalData.version_added && !originalData.version_removed) {
+      newData.version_removed = '79';
+    }
+  } else if (chromeNull) {
+    newData.version_added = null;
+  } else {
+    if (sourceData.version_added === true) {
+      newData.version_added =
+        originalData.version_added === true ? '≤18' : true;
+    } else if (compareVersions.compare(sourceData.version_added, '79', '<=')) {
+      newData.version_added =
+        originalData.version_added === null ? '≤79' : '79';
+    } else {
+      newData.version_added = sourceData.version_added;
+    }
+  }
+
+  let newNotes = updateNotes(sourceData.notes, /Chrome(?! ?OS)/g, 'Edge');
+  if (newNotes) newData.notes = newNotes;
+
+  return newData;
+};
+
+/**
+ * @param {SupportStatement} originalData
+ * @param {SupportStatement} chromeData
+ * @param {SupportStatement} ieData
+ * @param {string} source
+ * @returns {SupportStatement}
+ */
+const bumpEdge = (originalData, chromeData, ieData, source) => {
+  if (!['chrome-ie', 'chrome', 'ie'].includes(source)) {
+    throw new Error(
+      `Source browser "${source}" is invalid for Edge. Valid options are: chrome, ie, chrome-ie`,
+    );
+  }
 
-    let newNotes = combineNotes(
-      updateNotes(sourceData.notes, /Chrome/g, 'Edge'),
-      originalData.notes,
+  if (Array.isArray(originalData)) {
+    return combineStatements(
+      ...originalData.map((d) => bumpEdge(d, chromeData, ieData, source)),
     );
+  }
+
+  let newData = [];
 
-    if (newNotes) {
-      newData.notes = newNotes;
+  if (ieData && source.includes('ie')) {
+    if (Array.isArray(ieData)) {
+      newData = newData.concat(ieData.map((d) => bumpEdgeFromIE(d)));
+    } else {
+      newData.push(bumpEdgeFromIE(ieData));
     }
   }
 
-  return newData;
+  if (chromeData && source.includes('chrome')) {
+    if (Array.isArray(chromeData)) {
+      newData = newData.concat(
+        chromeData.map((d) => bumpEdgeFromChrome(d, originalData)),
+      );
+    } else {
+      newData.push(bumpEdgeFromChrome(chromeData, originalData));
+    }
+  }
+
+  return combineStatements(...newData);
 };
 
 /**
@@ -345,6 +462,12 @@ const bumpFirefoxAndroid = (originalData, sourceData) => {
  * @returns {SupportStatement}
  */
 const bumpOpera = (originalData, sourceData, source) => {
+  if (Array.isArray(sourceData)) {
+    return combineStatements(
+      ...sourceData.map((d) => bumpOpera(originalData, d, source)),
+    );
+  }
+
   let newData = copyStatement(sourceData);
 
   if (typeof sourceData.version_added === 'string') {
@@ -365,7 +488,7 @@ const bumpOpera = (originalData, sourceData, source) => {
   }
 
   if (typeof sourceData.notes === 'string') {
-    newData.notes = updateNotes(sourceData.notes, /Chrome/g, 'Opera');
+    newData.notes = updateNotes(sourceData.notes, /Chrome(?! ?OS)/g, 'Opera');
   }
 
   return newData;
@@ -378,6 +501,12 @@ const bumpOpera = (originalData, sourceData, source) => {
  * @returns {SupportStatement}
  */
 const bumpOperaAndroid = (originalData, sourceData, source) => {
+  if (Array.isArray(sourceData)) {
+    return combineStatements(
+      ...sourceData.map((d) => bumpOperaAndroid(originalData, d, source)),
+    );
+  }
+
   let newData = copyStatement(sourceData);
 
   if (typeof sourceData.version_added === 'string') {
@@ -398,7 +527,7 @@ const bumpOperaAndroid = (originalData, sourceData, source) => {
   }
 
   if (typeof sourceData.notes === 'string') {
-    newData.notes = updateNotes(sourceData.notes, /Chrome/g, 'Opera');
+    newData.notes = updateNotes(sourceData.notes, /Chrome(?! ?OS)/g, 'Opera');
   }
 
   return newData;
@@ -411,6 +540,12 @@ const bumpOperaAndroid = (originalData, sourceData, source) => {
  * @returns {SupportStatement}
  */
 const bumpSafariiOS = (originalData, sourceData, source) => {
+  if (Array.isArray(sourceData)) {
+    return combineStatements(
+      ...sourceData.map((d) => bumpSafariiOS(originalData, d, source)),
+    );
+  }
+
   let newData = copyStatement(sourceData);
 
   if (typeof sourceData.version_added === 'string') {
@@ -440,6 +575,12 @@ const bumpSafariiOS = (originalData, sourceData, source) => {
  * @returns {SupportStatement}
  */
 const bumpSamsungInternet = (originalData, sourceData, source) => {
+  if (Array.isArray(sourceData)) {
+    return combineStatements(
+      ...sourceData.map((d) => bumpSamsungInternet(originalData, d, source)),
+    );
+  }
+
   let newData = copyStatement(sourceData);
 
   if (typeof sourceData.version_added === 'string') {
@@ -462,7 +603,7 @@ const bumpSamsungInternet = (originalData, sourceData, source) => {
   if (typeof sourceData.notes === 'string') {
     newData.notes = updateNotes(
       sourceData.notes,
-      /Chrome/g,
+      /Chrome(?! ?OS)/g,
       'Samsung Internet',
     );
   }
@@ -504,7 +645,7 @@ const bumpWebView = (originalData, sourceData) => {
   }
 
   if (typeof sourceData.notes === 'string') {
-    newData.notes = updateNotes(sourceData.notes, /Chrome/g, 'WebView');
+    newData.notes = updateNotes(sourceData.notes, /Chrome(?! ?OS)/g, 'WebView');
   }
 
   return newData;
@@ -525,56 +666,28 @@ const bumpGeneric = (originalData, sourceData) => {
  * @param {string} destination
  * @param {string} source
  * @param {SupportStatement} originalData
+ * @param {SupportStatement} compData
  */
-const bumpVersion = (data, destination, source, originalData) => {
-  let newData = null;
+const bumpVersion = (data, destination, source, originalData, compData) => {
   if (data == null) {
     return null;
-  } else if (
-    Array.isArray(data) &&
-    !(destination == 'edge' && source == 'chrome')
-  ) {
-    newData = [];
-    for (let i = 0; i < data.length; i++) {
-      newData[i] = bumpVersion(data[i], destination, source, originalData);
-    }
-  } else {
-    let bumpFunction = null;
-
-    switch (destination) {
-      case 'chrome_android':
-        bumpFunction = bumpChromeAndroid;
-        break;
-      case 'edge':
-        bumpFunction = bumpEdge;
-        break;
-      case 'firefox_android':
-        bumpFunction = bumpFirefoxAndroid;
-        break;
-      case 'opera':
-        bumpFunction = bumpOpera;
-        break;
-      case 'opera_android':
-        bumpFunction = bumpOperaAndroid;
-        break;
-      case 'safari_ios':
-        bumpFunction = bumpSafariiOS;
-        break;
-      case 'samsunginternet_android':
-        bumpFunction = bumpSamsungInternet;
-        break;
-      case 'webview_android':
-        bumpFunction = bumpWebView;
-        break;
-      default:
-        bumpFunction = bumpGeneric;
-        break;
-    }
-
-    newData = bumpFunction(originalData, data, source);
   }
 
-  return newData;
+  const bumpFunctions = {
+    generic: bumpGeneric,
+    chrome_android: bumpChromeAndroid,
+    firefox_android: bumpFirefoxAndroid,
+    edge: (originalData, data, source) =>
+      bumpEdge(originalData, compData['chrome'], compData['ie'], source),
+    opera: bumpOpera,
+    opera_android: bumpOperaAndroid,
+    safari_ios: bumpSafariiOS,
+    samsunginternet_android: bumpSamsungInternet,
+    webview_android: bumpWebView,
+  };
+
+  let bumpFunction = bumpFunctions[destination] || bumpFunctions.generic;
+  return bumpFunction(originalData, data, source);
 };
 
 /**
@@ -587,7 +700,7 @@ const bumpVersion = (data, destination, source, originalData) => {
  @ @returns {Identifier}
  */
 const doSetFeature = (data, newData, rootPath, browser, source, modify) => {
-  let comp = data[rootPath].__compat.support;
+  let compData = data[rootPath].__compat.support;
 
   let doBump = false;
   if (modify == 'always') {
@@ -597,22 +710,28 @@ const doSetFeature = (data, newData, rootPath, browser, source, modify) => {
       modify == 'nonreal'
         ? [true, null, undefined]
         : [true, false, null, undefined];
-    if (Array.isArray(comp[browser])) {
-      for (let i = 0; i < comp[browser].length; i++) {
-        if (triggers.includes(comp[browser][i].version_added)) {
+    if (Array.isArray(compData[browser])) {
+      for (let i = 0; i < compData[browser].length; i++) {
+        if (triggers.includes(compData[browser][i].version_added)) {
           doBump = true;
           break;
         }
       }
-    } else if (comp[browser] !== undefined) {
-      doBump = triggers.includes(comp[browser].version_added);
+    } else if (compData[browser] !== undefined) {
+      doBump = triggers.includes(compData[browser].version_added);
     } else {
       doBump = true;
     }
   }
 
   if (doBump) {
-    let newValue = bumpVersion(comp[source], browser, source, comp[browser]);
+    let newValue = bumpVersion(
+      compData[source],
+      browser,
+      source,
+      compData[browser],
+      compData,
+    );
     if (newValue !== null) {
       newData[rootPath].__compat.support[browser] = newValue;
     }