--- a/netwerk/base/security-prefs.js
+++ b/netwerk/base/security-prefs.js
@@ -9,17 +9,16 @@ pref("security.tls.insecure_fallback_hos
 pref("security.tls.unrestricted_rc4_fallback", false);
 pref("security.tls.enable_0rtt_data", false);
 
 pref("security.ssl.treat_unsafe_negotiation_as_broken", false);
 pref("security.ssl.require_safe_negotiation",  false);
 pref("security.ssl.enable_ocsp_stapling", true);
 pref("security.ssl.enable_false_start", true);
 pref("security.ssl.false_start.require-npn", false);
-pref("security.ssl.enable_npn", true);
 pref("security.ssl.enable_alpn", true);
 
 pref("security.ssl3.ecdhe_rsa_aes_128_gcm_sha256", true);
 pref("security.ssl3.ecdhe_ecdsa_aes_128_gcm_sha256", true);
 pref("security.ssl3.ecdhe_ecdsa_chacha20_poly1305_sha256", true);
 pref("security.ssl3.ecdhe_rsa_chacha20_poly1305_sha256", true);
 pref("security.ssl3.ecdhe_ecdsa_aes_256_gcm_sha384", true);
 pref("security.ssl3.ecdhe_rsa_aes_256_gcm_sha384", true);

--- a/security/manager/ssl/nsNSSComponent.cpp
+++ b/security/manager/ssl/nsNSSComponent.cpp
@@ -1424,17 +1424,16 @@ nsNSSComponent::FillTLSVersionRange(SSLV
   // fill out rangeOut
   rangeOut.min = (uint16_t) minFromPrefs;
   rangeOut.max = (uint16_t) maxFromPrefs;
 }
 
 static const int32_t OCSP_ENABLED_DEFAULT = 1;
 static const bool REQUIRE_SAFE_NEGOTIATION_DEFAULT = false;
 static const bool FALSE_START_ENABLED_DEFAULT = true;
-static const bool NPN_ENABLED_DEFAULT = true;
 static const bool ALPN_ENABLED_DEFAULT = false;
 static const bool ENABLED_0RTT_DATA_DEFAULT = false;
 
 static void
 ConfigureTLSSessionIdentifiers()
 {
   bool disableSessionIdentifiers =
     Preferences::GetBool("security.ssl.disable_session_identifiers", false);
@@ -1880,23 +1879,20 @@ nsNSSComponent::InitializeNSS()
   SSL_OptionSetDefault(SSL_ENABLE_RENEGOTIATION, SSL_RENEGOTIATE_REQUIRES_XTN);
 
   SSL_OptionSetDefault(SSL_ENABLE_EXTENDED_MASTER_SECRET, true);
 
   SSL_OptionSetDefault(SSL_ENABLE_FALSE_START,
                        Preferences::GetBool("security.ssl.enable_false_start",
                                             FALSE_START_ENABLED_DEFAULT));
 
-  // SSL_ENABLE_NPN and SSL_ENABLE_ALPN also require calling
-  // SSL_SetNextProtoNego in order for the extensions to be negotiated.
-  // WebRTC does not do that so it will not use NPN or ALPN even when these
-  // preferences are true.
-  SSL_OptionSetDefault(SSL_ENABLE_NPN,
-                       Preferences::GetBool("security.ssl.enable_npn",
-                                            NPN_ENABLED_DEFAULT));
+  // SSL_ENABLE_ALPN also requires calling SSL_SetNextProtoNego in order for
+  // the extensions to be negotiated.
+  // WebRTC does not do that so it will not use ALPN even when this preference
+  // is true.
   SSL_OptionSetDefault(SSL_ENABLE_ALPN,
                        Preferences::GetBool("security.ssl.enable_alpn",
                                             ALPN_ENABLED_DEFAULT));
 
   SSL_OptionSetDefault(SSL_ENABLE_0RTT_DATA,
                        Preferences::GetBool("security.tls.enable_0rtt_data",
                                             ENABLED_0RTT_DATA_DEFAULT));
 
@@ -2091,20 +2087,16 @@ nsNSSComponent::Observe(nsISupports* aSu
       bool requireSafeNegotiation =
         Preferences::GetBool("security.ssl.require_safe_negotiation",
                              REQUIRE_SAFE_NEGOTIATION_DEFAULT);
       SSL_OptionSetDefault(SSL_REQUIRE_SAFE_NEGOTIATION, requireSafeNegotiation);
     } else if (prefName.EqualsLiteral("security.ssl.enable_false_start")) {
       SSL_OptionSetDefault(SSL_ENABLE_FALSE_START,
                            Preferences::GetBool("security.ssl.enable_false_start",
                                                 FALSE_START_ENABLED_DEFAULT));
-    } else if (prefName.EqualsLiteral("security.ssl.enable_npn")) {
-      SSL_OptionSetDefault(SSL_ENABLE_NPN,
-                           Preferences::GetBool("security.ssl.enable_npn",
-                                                NPN_ENABLED_DEFAULT));
     } else if (prefName.EqualsLiteral("security.ssl.enable_alpn")) {
       SSL_OptionSetDefault(SSL_ENABLE_ALPN,
                            Preferences::GetBool("security.ssl.enable_alpn",
                                                 ALPN_ENABLED_DEFAULT));
     } else if (prefName.EqualsLiteral("security.tls.enable_0rtt_data")) {
       SSL_OptionSetDefault(SSL_ENABLE_0RTT_DATA,
                            Preferences::GetBool("security.tls.enable_0rtt_data",
                                                 ENABLED_0RTT_DATA_DEFAULT));