diff --git a/tests/tests.py b/tests/tests.py
index 7dae0800..a394ec78 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -72,6 +72,11 @@ class TestsRequests:
                 200,
                 "application/xml; charset=UTF-8",
             ),
+            (
+                "static/favicons/site.webmanifest",
+                200,
+                "application/manifest+json; charset=UTF-8",
+            ),
             (
                 "static/fontawesome-free-5.0.2/css/fontawesome-all.min.css",
                 200,
diff --git a/webui.lua b/webui.lua
index 3c4fa5bc..184b428f 100644
--- a/webui.lua
+++ b/webui.lua
@@ -432,7 +432,7 @@ local function get_content_type(file_type)
   elseif file_type == 'mp3' then
     return 'audio/mpeg'
   elseif file_type == 'webmanifest' then
-    return 'application/manifest+json'
+    return 'application/manifest+json; charset=UTF-8'
   end
 end