--- a/browser/base/content/browser-places.js
+++ b/browser/base/content/browser-places.js
@@ -407,17 +407,17 @@ var PlacesCommandHook = {
       var description;
       var charset;
 
       let docInfo = await this._getPageDetails(aBrowser);
 
       try {
         title = docInfo.isErrorPage ? PlacesUtils.history.getPageTitle(uri)
                                     : aBrowser.contentTitle;
-        title = title || uri.spec;
+        title = title || uri.displaySpec;
         description = docInfo.description;
         charset = aBrowser.characterSet;
       } catch (e) { }
 
       if (aShowEditUI && isNewBookmark) {
         // If we bookmark the page here but open right into a cancelable
         // state (i.e. new bookmark in Library), start batching here so
         // all of the actions can be undone in a single undo step.

--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -2599,17 +2599,17 @@ function URLBarSetURI(aURI) {
   SetPageProxyState(valid ? "valid" : "invalid");
 }
 
 function losslessDecodeURI(aURI) {
   let scheme = aURI.scheme;
   if (scheme == "moz-action")
     throw new Error("losslessDecodeURI should never get a moz-action URI");
 
-  var value = aURI.spec;
+  var value = aURI.displaySpec;
 
   let decodeASCIIOnly = !["https", "http", "file", "ftp"].includes(scheme);
   // Try to decode as UTF-8 if there's no encoding sequence that we would break.
   if (!/%25(?:3B|2F|3F|3A|40|26|3D|2B|24|2C|23)/i.test(value)) {
     if (decodeASCIIOnly) {
       // This only decodes ascii characters (hex) 20-7e, except 25 (%).
       // This avoids both cases stipulated below (%-related issues, and \r, \n
       // and \t, which would be %0d, %0a and %09, respectively) as well as any
@@ -6576,17 +6576,17 @@ function warnAboutClosingWindow() {
   // the session alive. Hence don't prompt users to save tabs, but warn about
   // closing multiple tabs.
   return AppConstants.platform != "macosx"
          || (isPBWindow || gBrowser.warnAboutClosingTabs(gBrowser.closingTabsEnum.ALL));
 }
 
 var MailIntegration = {
   sendLinkForBrowser(aBrowser) {
-    this.sendMessage(aBrowser.currentURI.spec, aBrowser.contentTitle);
+    this.sendMessage(aBrowser.currentURI.displaySpec, aBrowser.contentTitle);
   },
 
   sendMessage(aBody, aSubject) {
     // generate a mailto url based on the url and the url's title
     var mailtoUrl = "mailto:";
     if (aBody) {
       mailtoUrl += "?body=" + encodeURIComponent(aBody);
       mailtoUrl += "&subject=" + encodeURIComponent(aSubject);
@@ -7627,17 +7627,17 @@ var gIdentityHandler = {
       this.refreshIdentityBlock();
     }
   },
 
   onDragStart(event) {
     if (gURLBar.getAttribute("pageproxystate") != "valid")
       return;
 
-    let value = gBrowser.currentURI.spec;
+    let value = gBrowser.currentURI.displaySpec;
     let urlString = value + "\n" + gBrowser.contentTitle;
     let htmlString = "<a href=\"" + value + "\">" + value + "</a>";
 
     let dt = event.dataTransfer;
     dt.setData("text/x-moz-url", urlString);
     dt.setData("text/uri-list", value);
     dt.setData("text/plain", value);
     dt.setData("text/html", htmlString);
@@ -8019,23 +8019,23 @@ function switchToTabHavingURI(aURI, aOpe
       }
       return ret;
     }
 
     // Need to handle nsSimpleURIs here too (e.g. about:...), which don't
     // work correctly with URL objects - so treat them as strings
     let ignoreFragmentWhenComparing = typeof ignoreFragment == "string" &&
                                       ignoreFragment.startsWith("whenComparing");
-    let requestedCompare = cleanURL(
-        aURI.spec, ignoreQueryString || replaceQueryString, ignoreFragmentWhenComparing);
+      let requestedCompare = cleanURL(
+          aURI.displaySpec, ignoreQueryString || replaceQueryString, ignoreFragmentWhenComparing);
     let browsers = aWindow.gBrowser.browsers;
     for (let i = 0; i < browsers.length; i++) {
       let browser = browsers[i];
       let browserCompare = cleanURL(
-          browser.currentURI.spec, ignoreQueryString || replaceQueryString, ignoreFragmentWhenComparing);
+          browser.currentURI.displaySpec, ignoreQueryString || replaceQueryString, ignoreFragmentWhenComparing);
       if (requestedCompare == browserCompare) {
         aWindow.focus();
         if (ignoreFragment == "whenComparingAndReplace" || replaceQueryString) {
           browser.loadURI(aURI.spec);
         }
         aWindow.gBrowser.tabContainer.selectedIndex = i;
         return true;
       }

--- a/browser/base/content/tabbrowser.xml
+++ b/browser/base/content/tabbrowser.xml
@@ -1433,21 +1433,21 @@
             if (aTab._suppressTransientPlaceholderLabel) {
               if (!title) {
                 return false;
               }
               delete aTab._suppressTransientPlaceholderLabel;
             }
 
             if (!title) {
-              if (browser.currentURI.spec) {
+              if (browser.currentURI.displaySpec) {
                 try {
-                  title = this.mURIFixup.createExposableURI(browser.currentURI).spec;
+                  title = this.mURIFixup.createExposableURI(browser.currentURI).displaySpec;
                 } catch (ex) {
-                  title = browser.currentURI.spec;
+                  title = browser.currentURI.displaySpec;
                 }
               }
 
               if (title && !isBlankPageURL(title)) {
                 // At this point, we now have a URI.
                 // Let's try to unescape it using a character set
                 // in case the URI is not ASCII.
                 try {
@@ -7660,17 +7660,17 @@
         tabcontainer.removeEventListener("TabAttrModified", this);
         tabcontainer.removeEventListener("TabClose", this);
       ]]></handler>
 
       <handler event="DOMMenuItemActive">
       <![CDATA[
         var tab = event.target.tab;
         if (tab) {
-          let overLink = tab.linkedBrowser.currentURI.spec;
+          let overLink = tab.linkedBrowser.currentURI.displaySpec;
           if (overLink == "about:blank")
             overLink = "";
           XULBrowserWindow.setOverLink(overLink, null);
         }
       ]]></handler>
 
       <handler event="DOMMenuItemInactive">
       <![CDATA[

--- a/browser/base/content/test/urlbar/browser_urlbarCopying.js
+++ b/browser/base/content/test/urlbar/browser_urlbarCopying.js
@@ -132,16 +132,29 @@ var tests = [
   {
     copyVal: "e<xample.com/\xe9>\xe9",
     copyExpected: "xample.com/\xe9"
   },
   {
     copyVal: "<example.com/\xe9>\xe9",
     copyExpected: "http://example.com/\xe9"
   },
+  { // Note: it seems BrowserTestUtils.loadURI fails for unicode domains
+    loadURL: "http://sub2.xn--lt-uia.mochi.test:8888/foo",
+    expectedURL: toUnicode("sub2.ält.mochi.test:8888/foo"),
+    copyExpected: toUnicode("http://sub2.ält.mochi.test:8888/foo")
+  },
+  {
+    copyVal: toUnicode("s<ub2.ält.mochi.test:8888/f>oo"),
+    copyExpected: toUnicode("ub2.ält.mochi.test:8888/f")
+  },
+  {
+    copyVal: toUnicode("<sub2.ält.mochi.test:8888/f>oo"),
+    copyExpected: toUnicode("http://sub2.ält.mochi.test:8888/f")
+  },
 
   {
     loadURL: "http://example.com/?%C3%B7%C3%B7",
     expectedURL: "example.com/?\xf7\xf7",
     copyExpected: "http://example.com/?%C3%B7%C3%B7"
   },
   {
     copyVal: "e<xample.com/?\xf7>\xf7",
@@ -206,16 +219,17 @@ function runTest(testCase, cb) {
     testCopy(testCase.copyVal, testCase.copyExpected, cb);
   }
 
   if (testCase.setup) {
     testCase.setup();
   }
 
   if (testCase.loadURL) {
+    info(`Loading : ${testCase.loadURL}\n`);
     loadURL(testCase.loadURL, doCheck);
   } else {
     if (testCase.setURL)
       gURLBar.value = testCase.setURL;
     doCheck();
   }
 }
 

--- a/browser/base/content/urlbarBindings.xml
+++ b/browser/base/content/urlbarBindings.xml
@@ -203,17 +203,17 @@ file, You can obtain one at http://mozil
               case "extension": {
                 returnValue = action.params.content;
                 break;
               }
             }
           } else {
             let originalUrl = ReaderMode.getOriginalUrlObjectForDisplay(aValue);
             if (originalUrl) {
-              returnValue = originalUrl.spec;
+              returnValue = originalUrl.displaySpec;
             }
           }
 
           // Set the actiontype only if the user is not overriding actions.
           if (action && this._pressedNoActionKeys.size == 0) {
             this.setAttribute("actiontype", action.type);
           } else {
             this.removeAttribute("actiontype");
@@ -836,38 +836,38 @@ file, You can obtain one at http://mozil
               uri = uriFixup.createFixupURI(inputVal, Ci.nsIURIFixup.FIXUP_FLAG_NONE);
             } catch (e) {}
             if (!uri)
               return selectedVal;
           }
 
           // Avoid copying 'about:reader?url=', and always provide the original URI:
           // Reader mode ensures we call createExposableURI itself.
-          let readerStrippedURI = ReaderMode.getOriginalUrlObjectForDisplay(uri.spec);
+          let readerStrippedURI = ReaderMode.getOriginalUrlObjectForDisplay(uri.displaySpec);
           if (readerStrippedURI) {
             uri = readerStrippedURI;
           } else {
             // Only copy exposable URIs
             try {
               uri = uriFixup.createExposableURI(uri);
             } catch (ex) {}
           }
 
           // If the entire URL is selected, just use the actual loaded URI,
           // unless we want a decoded URI, or it's a data: or javascript: URI,
           // since those are hard to read when encoded.
           if (inputVal == selectedVal &&
               !uri.schemeIs("javascript") && !uri.schemeIs("data") &&
               !Services.prefs.getBoolPref("browser.urlbar.decodeURLsOnCopy")) {
-            return uri.spec;
+            return uri.displaySpec;
           }
 
           // Just the beginning of the URL is selected, or we want a decoded
           // url. First check for a trimmed value.
-          let spec = uri.spec;
+          let spec = uri.displaySpec;
           let trimmedSpec = this.trimValue(spec);
           if (spec != trimmedSpec) {
             // Prepend the portion that trimValue removed from the beginning.
             // This assumes trimValue will only truncate the URL at
             // the beginning or end (or both).
             let trimmedSegments = spec.split(trimmedSpec);
             selectedVal = trimmedSegments[0] + selectedVal;
           }
@@ -1283,17 +1283,17 @@ file, You can obtain one at http://mozil
 
         // Drag only if the entire value is selected and it's a valid URI.
         var isFullSelection = this.selectionStart == 0 &&
                               this.selectionEnd == this.textLength;
         if (!isFullSelection ||
             this.getAttribute("pageproxystate") != "valid")
           return;
 
-        var urlString = gBrowser.selectedBrowser.currentURI.spec;
+        var urlString = gBrowser.selectedBrowser.currentURI.displaySpec;
         var title = gBrowser.selectedBrowser.contentTitle || urlString;
         var htmlString = "<a href=\"" + urlString + "\">" + urlString + "</a>";
 
         var dt = event.dataTransfer;
         dt.setData("text/x-moz-url", urlString + "\n" + title);
         dt.setData("text/unicode", urlString);
         dt.setData("text/html", htmlString);
 

--- a/browser/base/content/utilityOverlay.js
+++ b/browser/base/content/utilityOverlay.js
@@ -938,17 +938,17 @@ function trimURL(aURL) {
   }
   let urlWithoutProtocol = url.substring(7);
 
   let flags = Services.uriFixup.FIXUP_FLAG_ALLOW_KEYWORD_LOOKUP |
               Services.uriFixup.FIXUP_FLAG_FIX_SCHEME_TYPOS;
   let fixedUpURL, expectedURLSpec;
   try {
     fixedUpURL = Services.uriFixup.createFixupURI(urlWithoutProtocol, flags);
-    expectedURLSpec = makeURI(aURL).spec;
+    expectedURLSpec = makeURI(aURL).displaySpec;
   } catch (ex) {
     return url;
   }
-  if (fixedUpURL.spec == expectedURLSpec) {
+  if (fixedUpURL.displaySpec == expectedURLSpec) {
     return urlWithoutProtocol;
   }
   return url;
 }