diff --git a/.github/scripts/clean_xliff_targets.py b/.github/scripts/clean_xliff_targets.py
index 6615a7f4f..7c567558c 100644
--- a/.github/scripts/clean_xliff_targets.py
+++ b/.github/scripts/clean_xliff_targets.py
@@ -5,6 +5,7 @@
 
 # This script must be executed at the root of the repository.
 
+from functions import write_xliff
 from lxml import etree, objectify
 import argparse
 
@@ -49,13 +50,7 @@ def main():
         sort_children(f, "id")
 
     # Replace the existing local file with the new XML content
-    with open(xliff_file, "w") as fp:
-        # Fix indentation of XML file
-        etree.indent(root)
-        xliff_content = etree.tostring(
-            tree, encoding="UTF-8", xml_declaration=True, pretty_print=True
-        )
-        fp.write(xliff_content.decode("utf-8"))
+    write_xliff(root, xliff_file)
 
 
 if __name__ == "__main__":
diff --git a/.github/scripts/extract_source_strings.py b/.github/scripts/extract_source_strings.py
index 5f7b59520..b04d2b263 100644
--- a/.github/scripts/extract_source_strings.py
+++ b/.github/scripts/extract_source_strings.py
@@ -5,6 +5,7 @@
 
 # This script must be executed at the root of the repository.
 
+from functions import write_xliff
 from lxml import etree, objectify
 import argparse
 import os
@@ -116,13 +117,7 @@ def main():
         sort_children(f, "id")
 
     # Replace the existing local file with the new XML content
-    with open(output_xliff_file, "w") as fp:
-        # Fix indentation of XML file
-        etree.indent(root)
-        xliff_content = etree.tostring(
-            tree, encoding="UTF-8", xml_declaration=True, pretty_print=True
-        )
-        fp.write(xliff_content.decode("utf-8"))
+    write_xliff(root, output_xliff_file)
 
 
 if __name__ == "__main__":
diff --git a/.github/scripts/functions.py b/.github/scripts/functions.py
new file mode 100644
index 000000000..6a365f8da
--- /dev/null
+++ b/.github/scripts/functions.py
@@ -0,0 +1,23 @@
+from lxml import etree
+
+
+def write_xliff(root, filename):
+    with open(filename, "w+") as fp:
+        # Fix identation of XML file
+        etree.indent(root)
+        """
+        Hack to avoid conflicts with Pontoon, which uses single quotes
+        for the XML declaration:
+            1. Exclude the XML declaration when using etree.tostring()
+            2. Manually add the declaration with double quotes
+        """
+        xliff_content = etree.tostring(
+            root,
+            encoding="UTF-8",
+            xml_declaration=False,
+            pretty_print=True,
+        )
+        xliff_content = (
+            '<?xml version="1.0" encoding="UTF-8"?>\n' + xliff_content.decode("utf-8")
+        )
+        fp.write(xliff_content)
diff --git a/.github/scripts/set_target_language_en.py b/.github/scripts/set_target_language_en.py
index 6e7eb7c1f..7c508055b 100644
--- a/.github/scripts/set_target_language_en.py
+++ b/.github/scripts/set_target_language_en.py
@@ -3,6 +3,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+from functions import write_xliff
 from glob import glob
 from lxml import etree
 import argparse
@@ -25,13 +26,7 @@ def main():
         for file_node in root.xpath("//x:file", namespaces=NS):
             file_node.set("target-language", "en-US")
 
-        with open(xliff_path, "w") as fp:
-            # Fix indentation of XML file
-            etree.indent(root)
-            xliff_content = etree.tostring(
-                tree, encoding="UTF-8", xml_declaration=True, pretty_print=True
-            )
-            fp.write(xliff_content.decode("utf-8"))
+        write_xliff(root, xliff_path)
 
 
 if __name__ == "__main__":
diff --git a/.github/scripts/update_other_locales.py b/.github/scripts/update_other_locales.py
index bcdf26704..aca6938be 100644
--- a/.github/scripts/update_other_locales.py
+++ b/.github/scripts/update_other_locales.py
@@ -26,6 +26,7 @@
 
 from argparse import RawTextHelpFormatter
 from copy import deepcopy
+from functions import write_xliff
 from glob import glob
 from lxml import etree
 import argparse
@@ -219,16 +220,7 @@ def main():
 
             # Replace the existing locale file with the new XML content,
             # or create a new one if it's missing.
-            with open(l10n_file, "w+") as fp:
-                # Fix identation of XML file
-                etree.indent(reference_root_copy)
-                xliff_content = etree.tostring(
-                    reference_tree_copy,
-                    encoding="UTF-8",
-                    xml_declaration=True,
-                    pretty_print=True,
-                )
-                fp.write(xliff_content.decode("utf-8"))
+            write_xliff(reference_root_copy, l10n_file)
             updated_files += 1
 
     if updated_files == 0:
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..0d20b6487
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.pyc