diff --git a/gstreamer-app/Gir.toml b/gstreamer-app/Gir.toml
index 440379423..c064123bc 100644
--- a/gstreamer-app/Gir.toml
+++ b/gstreamer-app/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -138,12 +139,6 @@ final_type = true
     # Use callbacks instead
     ignore = true
 
-    [[object.function]]
-    name = "set_caps"
-        [[object.function.parameter]]
-        name = "caps"
-        nullable = true
-
     [[object.function]]
     name = "pull_preroll"
         [object.function.return]
@@ -233,9 +228,3 @@ final_type = true
     name = "get_latency"
     # ClockTime
     manual = true
-
-    [[object.function]]
-    name = "set_caps"
-        [[object.function.parameter]]
-            name = "caps"
-            nullable = true
diff --git a/gstreamer-audio/Gir.toml b/gstreamer-audio/Gir.toml
index 292ae0b10..dfbec6810 100644
--- a/gstreamer-audio/Gir.toml
+++ b/gstreamer-audio/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -192,16 +193,6 @@ manual_traits = ["AudioDecoderExtManual"]
     name = "get_allocator"
     manual = true
 
-    [[object.function]]
-    name = "proxy_getcaps"
-        [object.function.return]
-        nullable = false
-
-    [[object.function]]
-    name = "allocate_output_buffer"
-        [object.function.return]
-        nullable_return_is_error = "Failed to allocate output buffer"
-
 [[object]]
 name = "GstAudio.AudioEncoder"
 status = "generate"
@@ -234,11 +225,6 @@ manual_traits = ["AudioEncoderExtManual"]
         [object.function.return]
         mandatory = true
 
-    [[object.function]]
-    name = "proxy_getcaps"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "set_latency"
         [[object.function.parameter]]
@@ -251,11 +237,6 @@ manual_traits = ["AudioEncoderExtManual"]
         name = "tolerance"
         mandatory = true
 
-    [[object.function]]
-    name = "allocate_output_buffer"
-        [object.function.return]
-        nullable_return_is_error = "Failed to allocate output buffer"
-
 [[object]]
 name = "GstAudio.AudioFlags"
 status = "generate"
@@ -344,8 +325,6 @@ status = "generate"
     name = "to_string"
     # This has an Unknown field that may return NULL or "UNKNOWN"
     manual = true
-        [object.function.return]
-        nullable = false
 
     [[object.function]]
     name = "fill_silence"
diff --git a/gstreamer-controller/Gir.toml b/gstreamer-controller/Gir.toml
index 276fcc671..7a282b108 100644
--- a/gstreamer-controller/Gir.toml
+++ b/gstreamer-controller/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
diff --git a/gstreamer-editing-services/Gir.toml b/gstreamer-editing-services/Gir.toml
index 2fc2f1002..2c7a4707c 100644
--- a/gstreamer-editing-services/Gir.toml
+++ b/gstreamer-editing-services/Gir.toml
@@ -7,6 +7,7 @@ work_mode = "normal"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "Gio",
@@ -59,6 +60,9 @@ generate = [
     "GES.BaseXmlFormatter",
     "GES.ChildrenControlMode",
     "GES.ClipAsset",
+    "GES.CommandLineFormatter",
+    "GES.Edge",
+    "GES.EditMode",
     "GES.EffectAsset",
     "GES.EffectClip",
     "GES.Error",
@@ -88,6 +92,7 @@ generate = [
     "GES.TitleClip",
     "GES.TitleSource",
     "GES.TrackElementAsset",
+    "GES.TrackType",
     "GES.Transition",
     "GES.TransitionClip",
     "GES.UriClipAsset",
@@ -156,18 +161,6 @@ status = "generate"
         [object.function.return]
         nullable_return_is_error = "Failed to split clip"
 
-[[object]]
-name = "GES.CommandLineFormatter"
-status = "generate"
-    [[object.function]]
-    name = "get_help"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
-    name = "get_timeline_uri"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GES.Container"
 status = "generate"
@@ -187,22 +180,6 @@ trait_name = "GESContainerExt"
         [object.function.return]
         bool_return_is_error = "Failed to edit container"
 
-[[object]]
-name = "GES.Edge"
-status = "generate"
-    [[object.function]]
-    name = "name"
-        [object.function.return]
-        nullable = false
-
-[[object]]
-name = "GES.EditMode"
-status = "generate"
-    [[object.function]]
-    name = "name"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GES.Effect"
 status = "generate"
@@ -282,11 +259,6 @@ status = "generate"
 [[object]]
 name = "GES.Timeline"
 status = "generate"
-    [[object.function]]
-    name = "append_layer"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "get_duration"
         [object.function.return]
@@ -449,11 +421,6 @@ manual_traits = ["TimelineElementExtManual"]
         [object.function.return]
         bool_return_is_error = "Failed to trim"
 
-    [[object.function]]
-    name = "copy"
-        [object.function.return]
-        nullable_return_is_error = "Failed to copy timeline element"
-
 [[object]]
 name = "GES.Track"
 status = "generate"
@@ -495,14 +462,6 @@ status = "generate"
         name = "value"
         const = true
 
-[[object]]
-name = "GES.TrackType"
-status = "generate"
-    [[object.function]]
-    name = "name"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GES.UriClip"
 status = "generate"
diff --git a/gstreamer-gl/Gir.toml b/gstreamer-gl/Gir.toml
index fbff053c8..e384508b6 100644
--- a/gstreamer-gl/Gir.toml
+++ b/gstreamer-gl/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -230,11 +231,6 @@ status = "generate"
     name = "any"
     ignore = true
 
-    [[object.function]]
-    name = "to_string"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstGL.GLBuffer"
 status = "manual"
@@ -321,11 +317,6 @@ manual_traits = ["GLContextExtManual"]
         [object.function.return]
         bool_return_is_error = "Failed to activate OpenGL context"
 
-    [[object.function]]
-    name = "get_display"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "set_window"
         [object.function.return]
@@ -434,11 +425,6 @@ status = "generate"
     name = "any"
     ignore = true
 
-    [[object.function]]
-    name = "to_string"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstGL.GLQuery"
 status = "manual"
@@ -544,11 +530,6 @@ final_type = true
     # fix mutability
     ignore = true
 
-    [[object.function]]
-    name = "get_input_template_caps"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstGL.GLVideoAllocationParams"
 status = "generate"
@@ -585,11 +566,6 @@ final_type = true
     # Result<Buffer, FlowReturn>
     ignore = true
 
-    [[object.function]]
-    name = "transform_caps"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "submit_input_buffer"
     # Buffer ownership transfer
diff --git a/gstreamer-net/Gir.toml b/gstreamer-net/Gir.toml
index 73be0bfd8..f12223924 100644
--- a/gstreamer-net/Gir.toml
+++ b/gstreamer-net/Gir.toml
@@ -43,6 +43,10 @@ final_type = true
 name = "GstNet.NetTimeProvider"
 status = "generate"
 final_type = true
+    [[object.function]]
+    name = "new"
+        [object.function.return]
+        nullable_return_is_error = "Failed to create NetTimeProvider"
 
 [[object]]
 name = "GstNet.NtpClock"
diff --git a/gstreamer-pbutils/Gir.toml b/gstreamer-pbutils/Gir.toml
index 11650e4fc..5e1661e10 100644
--- a/gstreamer-pbutils/Gir.toml
+++ b/gstreamer-pbutils/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -18,6 +19,7 @@ external_libraries = [
 generate = [
     "GstPbutils.AudioVisualizer",
     "GstPbutils.AudioVisualizerShader",
+    "GstPbutils.DiscovererInfo",
     "GstPbutils.DiscovererResult",
     "GstPbutils.PbUtilsCapsDescriptionFlags",
 ]
@@ -209,26 +211,9 @@ status = "generate"
     name = "pb_utils_get_encoder_description"
     ignore = true
 
-    [[object.function]]
-    name = "pb_utils_get_element_description"
-        [object.function.return]
-        nullable_return_is_error = "Failed to get element description"
-
-    [[object.function]]
-    name = "pb_utils_get_sink_description"
-        [object.function.return]
-        nullable_return_is_error = "Failed to get sink description"
-
-    [[object.function]]
-    name = "pb_utils_get_source_description"
-        [object.function.return]
-        nullable_return_is_error = "Failed to get source description"
-
     [[object.function]]
     name = "plugins_base_version_string"
     assertion = "skip"
-        [object.function.return]
-        nullable = false
 
     [[object.function]]
     name = "plugins_base_version"
@@ -269,25 +254,6 @@ name = "GstPbutils.DiscovererContainerInfo"
 status = "generate"
 final_type = true
 
-[[object]]
-name = "GstPbutils.DiscovererInfo"
-status = "generate"
-
-    [[object.function]]
-    name = "copy"
-        [object.function.return]
-        nullable = false
-
-    [[object.function]]
-    name = "to_variant"
-        [object.function.return]
-        nullable_return_is_error = "Failed to serialize DiscovererInfo to Variant"
-
-    [[object.function]]
-    name = "from_variant"
-        [object.function.return]
-        nullable_return_is_error = "Failed to deserialize DiscovererInfo from Variant"
-
 [[object]]
 name = "GstPbutils.DiscovererSerializeFlags"
 status = "generate"
@@ -308,11 +274,6 @@ final_type = false
     name = "list_free"
     ignore = true
 
-    [[object.function]]
-    name = "get_stream_type_nick"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstPbutils.DiscovererSubtitleInfo"
 status = "generate"
@@ -378,21 +339,6 @@ status = "generate"
     pattern = "get_restriction"
     manual = true
 
-    [[object.function]]
-    name = "copy"
-        [object.function.return]
-        nullable = false
-
-    [[object.function]]
-    name = "get_input_caps"
-        [object.function.return]
-        nullable = false
-
-    [[object.function]]
-    name = "get_format"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "get_element_properties"
     # Use custom wrapper types
@@ -419,17 +365,9 @@ status = "generate"
     ignore = true
 
     [[object.function]]
-    name = "get_category"
+    name = "new"
         [object.function.return]
-        nullable = false
-    [[object.function]]
-    name = "get_description"
-        [object.function.return]
-        nullable = false
-    [[object.function]]
-    name = "get_name"
-        [object.function.return]
-        nullable = false
+        nullable_return_is_error = "Failed to create EncodingTarget"
 
 [[object]]
 name = "GstPbutils.EncodingVideoProfile"
diff --git a/gstreamer-play/Gir.toml b/gstreamer-play/Gir.toml
index 824b8581d..8ce97ea73 100644
--- a/gstreamer-play/Gir.toml
+++ b/gstreamer-play/Gir.toml
@@ -156,9 +156,6 @@ final_type = true
     [[object.signal]]
     name = "error"
     concurrency = "send"
-        [[object.signal.parameter]]
-        name = "p0"
-        nullable = true
 
     [[object.signal]]
     name = "media-info-updated"
@@ -199,9 +196,6 @@ final_type = true
     [[object.signal]]
     name = "warning"
     concurrency = "send"
-        [[object.signal.parameter]]
-        name = "p0"
-        nullable = true
 
 [[object]]
 name = "GstPlay.PlaySubtitleInfo"
diff --git a/gstreamer-rtp/Gir.toml b/gstreamer-rtp/Gir.toml
index e160e7c2f..bb0d45489 100644
--- a/gstreamer-rtp/Gir.toml
+++ b/gstreamer-rtp/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -93,11 +94,6 @@ status = "generate"
     # Move buffer list
     manual = true
 
-    [[object.signal]]
-    name = "request-extension"
-        [object.signal.return]
-        nullable = true
-
 [[object]]
 name = "GstRtp.RTPBasePayload"
 status = "generate"
@@ -124,16 +120,6 @@ manual_traits = ["RTPHeaderExtensionExtManual"]
     manual = true
     rename = "set_outcaps"
 
-    [[object.function]]
-    name = "allocate_output_buffer"
-        [object.function.return]
-        nullable_return_is_error = "Failed to allocate output buffer"
-
-    [[object.signal]]
-    name = "request-extension"
-        [object.signal.return]
-        nullable = true
-
 [[object]]
 name = "GstRtp.RTPBuffer"
 status = "manual"
@@ -179,8 +165,3 @@ manual_traits = ["RTPHeaderExtensionExtManual"]
     name = "update_non_rtp_src_caps"
     # Mutability of CapsRef
     manual = true
-
-    [[object.function]]
-    name = "get_sdp_caps_field_name"
-        [object.function.return]
-        nullable = false
diff --git a/gstreamer-rtsp-server/Gir.toml b/gstreamer-rtsp-server/Gir.toml
index 388d5a895..de63dc4c1 100644
--- a/gstreamer-rtsp-server/Gir.toml
+++ b/gstreamer-rtsp-server/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "Gio",
@@ -152,11 +153,6 @@ manual_traits = ["RTSPAuthExtManual"]
     # Use Result<(), LoggableError>
     manual = true
 
-    [[object.function]]
-    name = "make_basic"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "set_default_token"
     # gir forgets mut
@@ -270,11 +266,6 @@ manual_traits = ["RTSPServerExtManual"]
 [[object]]
 name="GstRtspServer.RTSPSession"
 status="generate"
-    [[object.function]]
-    name = "manage_media"
-        [object.function.return]
-        nullable_return_is_error = "Failed to manage media"
-
     [[object.function]]
     name = "get_media"
     # Map to dup_media if new enough as get_media is not thread-safe
diff --git a/gstreamer-rtsp/Gir.toml b/gstreamer-rtsp/Gir.toml
index 1f90c01ae..537e7811c 100644
--- a/gstreamer-rtsp/Gir.toml
+++ b/gstreamer-rtsp/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "Gio",
diff --git a/gstreamer-sdp/Gir.toml b/gstreamer-sdp/Gir.toml
index 1e0a86793..e0febf389 100644
--- a/gstreamer-sdp/Gir.toml
+++ b/gstreamer-sdp/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
diff --git a/gstreamer-validate/Gir.toml b/gstreamer-validate/Gir.toml
index 367a46519..aadefd7f4 100644
--- a/gstreamer-validate/Gir.toml
+++ b/gstreamer-validate/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -52,4 +53,4 @@ manual = [
 [[object]]
 name = "GstValidate.Scenario"
 status = "generate"
-concurrency = "none"
\ No newline at end of file
+concurrency = "none"
diff --git a/gstreamer-video/Gir.toml b/gstreamer-video/Gir.toml
index e3ed5690f..eb6725243 100644
--- a/gstreamer-video/Gir.toml
+++ b/gstreamer-video/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -495,11 +496,6 @@ manual_traits = ["VideoDecoderExtManual"]
     name = "get_allocator"
     manual = true
 
-    [[object.function]]
-    name = "proxy_getcaps"
-        [object.function.return]
-        nullable = false
-
     [[object.function]]
     name = "allocate_output_buffer"
         [object.function.return]
@@ -562,16 +558,6 @@ manual_traits = ["VideoEncoderExtManual"]
     name = "get_allocator"
     manual = true
 
-    [[object.function]]
-    name = "proxy_getcaps"
-        [object.function.return]
-        nullable = false
-
-    [[object.function]]
-    name = "allocate_output_buffer"
-        [object.function.return]
-        nullable_return_is_error = "Failed to allocate output buffer"
-
 [[object]]
 name = "GstVideo.VideoFieldOrder"
 status = "generate"
@@ -580,8 +566,6 @@ status = "generate"
     name = "to_string"
     # This has an Unknown field that may return NULL or "UNKNOWN"
     manual = true
-        [object.function.return]
-        nullable = false
 
 [[object]]
 name = "GstVideo.VideoFlags"
@@ -665,8 +649,6 @@ status = "generate"
     name = "to_string"
     # This has an Unknown field that may return NULL or "UNKNOWN"
     manual = true
-        [object.function.return]
-        nullable = false
 
     [[object.function]]
     name = "get_info"
@@ -708,11 +690,6 @@ status = "generate"
     name = "alternate"
     version = "1.16"
 
-    [[object.function]]
-    name = "to_string"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstVideo.VideoMultiviewFlags"
 status = "generate"
diff --git a/gstreamer-webrtc/Gir.toml b/gstreamer-webrtc/Gir.toml
index 102fce5a3..4509c6a84 100644
--- a/gstreamer-webrtc/Gir.toml
+++ b/gstreamer-webrtc/Gir.toml
@@ -8,6 +8,7 @@ concurrency = "send+sync"
 generate_safety_asserts = true
 single_version_file = true
 generate_display_trait = false
+trust_return_value_nullability = true
 
 external_libraries = [
     "GLib",
@@ -36,6 +37,7 @@ generate = [
     "GstWebRTC.WebRTCPriorityType",
     "GstWebRTC.WebRTCRTPTransceiverDirection",
     "GstWebRTC.WebRTCSCTPTransportState",
+    "GstWebRTC.WebRTCSDPType",
     "GstWebRTC.WebRTCSignalingState",
     "GstWebRTC.WebRTCStatsType",
 ]
@@ -89,15 +91,6 @@ name = "GstWebRTC.WebRTCSCTPTransport"
 status = "generate"
 version = "1.20"
 
-[[object]]
-name = "GstWebRTC.WebRTCSDPType"
-status = "generate"
-
-    [[object.function]]
-    name = "to_string"
-        [object.function.return]
-        nullable = false
-
 [[object]]
 name = "GstWebRTC.WebRTCSessionDescription"
 status = "generate"
diff --git a/gstreamer/Gir.toml b/gstreamer/Gir.toml
index 1a66f9cf3..b05d65b88 100644
--- a/gstreamer/Gir.toml
+++ b/gstreamer/Gir.toml
@@ -857,22 +857,16 @@ status = "generate"
     name = "new_y"
     # Needs manual checking of invariants
     manual = true
-        [object.function.return]
-        nullable = true
 
     [[object.function]]
     name = "new_ym"
     # Needs manual checking of invariants
     manual = true
-        [object.function.return]
-        nullable = true
 
     [[object.function]]
     name = "new_ymd"
     # Needs manual checking of invariants
     manual = true
-        [object.function.return]
-        nullable = true
 
     [[object.function]]
     name = "get_month"