diff -up firefox-65.0/netwerk/protocol/http/nsHttpHandler.cpp.fedora-ua firefox-65.0/netwerk/protocol/http/nsHttpHandler.cpp
--- firefox-65.0/netwerk/protocol/http/nsHttpHandler.cpp.fedora-ua	2019-01-28 14:28:35.806375063 +0100
+++ firefox-65.0/netwerk/protocol/http/nsHttpHandler.cpp	2019-01-28 14:30:25.886917219 +0100
@@ -873,6 +873,7 @@ void nsHttpHandler::BuildUserAgent() {
   mUserAgent.SetCapacity(mLegacyAppName.Length() + mLegacyAppVersion.Length() +
 #ifndef UA_SPARE_PLATFORM
                          mPlatform.Length() +
+                         mPlatform.Length() + 8 +
 #endif
                          mOscpu.Length() + mMisc.Length() + mProduct.Length() +
                          mProductSub.Length() + mAppName.Length() +
@@ -891,6 +892,7 @@ void nsHttpHandler::BuildUserAgent() {
   if (!mPlatform.IsEmpty()) {
     mUserAgent += mPlatform;
     mUserAgent.AppendLiteral("; ");
+    mUserAgent.AppendLiteral("Fedora; ");
   }
 #endif
   if (!mCompatDevice.IsEmpty()) {