diff --git a/src/Html/Abstractions/src/PublicAPI.Shipped.txt b/src/Html/Abstractions/src/PublicAPI.Shipped.txt
new file mode 100644
index 000000000000..7dc5c58110bf
--- /dev/null
+++ b/src/Html/Abstractions/src/PublicAPI.Shipped.txt
@@ -0,0 +1 @@
+#nullable enable
diff --git a/src/Html/Abstractions/src/PublicAPI.Unshipped.txt b/src/Html/Abstractions/src/PublicAPI.Unshipped.txt
new file mode 100644
index 000000000000..32f03547bf81
--- /dev/null
+++ b/src/Html/Abstractions/src/PublicAPI.Unshipped.txt
@@ -0,0 +1,44 @@
+#nullable enable
+Microsoft.AspNetCore.Html.HtmlContentBuilder
+Microsoft.AspNetCore.Html.HtmlContentBuilder.Append(string? unencoded) -> Microsoft.AspNetCore.Html.IHtmlContentBuilder!
+Microsoft.AspNetCore.Html.HtmlContentBuilder.AppendHtml(Microsoft.AspNetCore.Html.IHtmlContent? htmlContent) -> Microsoft.AspNetCore.Html.IHtmlContentBuilder!
+Microsoft.AspNetCore.Html.HtmlContentBuilder.AppendHtml(string? encoded) -> Microsoft.AspNetCore.Html.IHtmlContentBuilder!
+Microsoft.AspNetCore.Html.HtmlContentBuilder.Clear() -> Microsoft.AspNetCore.Html.IHtmlContentBuilder!
+Microsoft.AspNetCore.Html.HtmlContentBuilder.CopyTo(Microsoft.AspNetCore.Html.IHtmlContentBuilder! destination) -> void
+Microsoft.AspNetCore.Html.HtmlContentBuilder.Count.get -> int
+Microsoft.AspNetCore.Html.HtmlContentBuilder.HtmlContentBuilder() -> void
+Microsoft.AspNetCore.Html.HtmlContentBuilder.HtmlContentBuilder(System.Collections.Generic.IList