diff --git a/mozilla-mobile/fenix/app/src/main/res/values/strings.xml b/mozilla-mobile/fenix/app/src/main/res/values/strings.xml
index c4a6ec0a6a6..36607e83cc2 100644
--- a/mozilla-mobile/fenix/app/src/main/res/values/strings.xml
+++ b/mozilla-mobile/fenix/app/src/main/res/values/strings.xml
@@ -1622,6 +1622,12 @@
     <!-- Description message for the alert dialog when the file cannot be renamed. -->
     <string name="download_rename_error_cannot_rename_description">This file can’t be renamed due to system or storage restrictions.</string>
     <string name="download_rename_error_dismiss_button">OK</string>
+    <!-- Title for the alert dialog to change file extension.
+         %s is the file type to change to. -->
+    <string name="change_file_extension_title">Change file type to %s?</string>
+    <string name="change_file_extension_description">This might open the file in a different app and be risky for your device.</string>
+    <string name="change_file_extension_cancel_button">Cancel</string>
+    <string name="change_file_extension_confirm_button">Yes, change it</string>
     <!-- Text for the header of in progress downloads -->
     <string name="download_header_in_progress">In progress</string>
     <!-- Time period headers for downloads -->