this code generates a copy of officedaytime’s intrinsic guide, but for .NET Core

Program.cs

using HtmlAgilityPack;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Xml.Linq;
using System.Xml.XPath;

// generated page is hosted at https://drachev.com/officedaytime/
// more details at https://habr.com/ru/post/507074/ (in Russian)

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            var htmlDir = @"html";
            Directory.CreateDirectory("html");
            if (!File.Exists(Path.Combine(htmlDir, "odt.html"))) {
                using var client = new WebClient();
                Console.WriteLine($"Downloading HTML ...");
                client.DownloadFile("https://www.officedaytime.com/simd512e/", Path.Combine(htmlDir, "odt.html"));
            }
            var doc = new HtmlDocument();
            doc.Load(Path.Combine(htmlDir, "odt.html"));
            var xmlDoc = XDocument.Load(@"C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\3.1.0\ref\netcoreapp3.1\System.Runtime.Intrinsics.xml");
            var summaries = xmlDoc.XPathSelectElements("//summary");
            foreach (var intr in doc.DocumentNode.SelectNodes("//span[@class='intr' or @class='intr_S1' or @class='intr_S2']").ToArray()) {
                var newParts = new List<string>();
                var parts = intr.InnerHtml.Split("<br>").Select(s => s.Trim()).ToArray();
                foreach (var part in parts) {
                    newParts.Add(part);
                    if (part != "") {
                        var p = Unbrace(part.Replace(" ", ""));
                        if (p.Contains("/")) {
                            var leftRight = new List<string>();
                            var converted = p.Split("/").Select(pp => MapFunc(summaries, pp).FirstOrDefault());
                            if (converted.Any(co => co != null))
                                newParts.Add(string.Join(" / ", converted));
                        } else {
                            newParts.AddRange(MapFunc(summaries, p));
                        }
                    }
                }
                intr.InnerHtml = string.Join("<br>", newParts);
            }
            foreach (var a in doc.DocumentNode.SelectNodes("//a[@href]")) {
                var origLink = a.Attributes["href"].Value;
                if (!origLink.StartsWith("http"))
                    a.Attributes["href"].Value = new Uri(new Uri("https://www.officedaytime.com/simd512e/"), origLink).ToString();
            }
            foreach (var a in doc.DocumentNode.SelectNodes("//img[@src]")) {
                var origLink = a.Attributes["src"].Value;
                if (!origLink.StartsWith("http") && !origLink.StartsWith("/")) {
                    var target = Path.Combine(htmlDir, origLink);
                    if (!File.Exists(target)) {
                        Directory.CreateDirectory(Path.GetDirectoryName(target));
                        using var client = new WebClient();
                        Console.WriteLine($"Downloading {origLink}...");
                        client.DownloadFile("https://www.officedaytime.com/simd512e/" + origLink, target);
                    }
                }
            }
            doc.DocumentNode.SelectSingleNode("html/head").AppendChild(
                HtmlNode.CreateNode("<style type=\"text/css\">.dotnet { color:rgb(0,147,181) } .dotnet a { text-decoration:none }</style>"));
            doc.DocumentNode.SelectSingleNode("html/head/title").InnerHtml += " adapted for .NET Core";
            foreach (var link in doc.DocumentNode.SelectNodes("html/head/link[@rel='alternate']"))
                link.Remove();
            var helpDoc = new HtmlDocument();
            helpDoc.LoadHtml(@"<b>What is this page?</b>
    <p>
        This page is a copy of a great x64 SIMD guide from
        <a href='https://www.officedaytime.com/simd512e/'>https://www.officedaytime.com/simd512e/</a>, but adapted for those of us who use C#.
    </p>
    <p>
        I amended it to include the names of intrinsics from the <b>System.Runtime.Intrinsics.X86</b> namespace as of .NET Core 3.1 (future versions pending).<br />
        These names are hard to find in MSDN documentation, and they differ from both Intel’s instruction names and C++ intrinsics. Hence, here they are.
    </p>
    <p>
        C# names, when awailable, are written below C++ intrinsics.
    </p>
    <p>
        ♯ — links to MSDN documentation are marked with a <i>sharp</i> sign.
    </p>
    <p>
        Some methods not included here are available for AVX and AVX2.
        If you can not find what you want, please try and change class name from <b>SseX</b> to <b>Avx</b> or <b>Avx2</b>.
        <br>
        Same deal with <b>Vector256</b>/<b>Vector128</b>.
        <br>
        <b>AVX512</b> is completely missing from .NET Core at this point. To highlight only AVX2 instructions, use <a href='?mf=0&amp;mt=8&amp;mc=0'>this link</a>.
    </p>");
            doc.DocumentNode.SelectSingleNode("html/body/span").Remove();
            var replacedA = doc.DocumentNode.SelectSingleNode("html/body/a");
            replacedA.ParentNode.ReplaceChild(helpDoc.DocumentNode, replacedA);
            var lastBr = doc.DocumentNode.SelectSingleNode("html/body/br[last()]");
            RemoveNodesAfter(lastBr);
            lastBr.ParentNode.InsertAfter(HtmlNode.CreateNode(
                @"<p>Original content by <a href='https://www.officedaytime.com/simd512e/'>daytime</a>. Instruction names © Intel, .net method names © Microsoft.</p>"
            ), lastBr);
            doc.Save(Path.Combine(htmlDir, "index.html"));
        }

        static void RemoveNodesAfter(HtmlNode node)
        {
            node = node.NextSibling;
            while (node != null) {
                var next = node.NextSibling;
                node.Remove();
                node = next;
            }
        }

        static string Unbrace(string s)
        {
            var brace = s.IndexOf('(');
            return brace != -1 ? s[..brace] : s;
        }

        static Dictionary<string, string> MyMap = new Dictionary<string, string> {
            { " _mm_set_epi64x _mm_set_epi32 _mm_set_epi16 _mm_set_epi8 _mm_set_pd _mm_set_ps ", "M:System.Runtime.Intrinsics.Vector256.Create" },
            { " _mm_setzero_si128 _mm_setzero_pd _mm_setzero_ps " ,"P:System.Runtime.Intrinsics.Vector256`1.Zero" },
            { " _mm_slli_si128 ", "M:System.Runtime.Intrinsics.X86.Sse2.ShiftLeftLogical128BitLane"},
            { " _mm_srli_si128 ", "M:System.Runtime.Intrinsics.X86.Sse2.ShiftRightLogical128BitLane"},
        };

        static string[] MapFunc(IEnumerable<XElement> summaries, string p)
        {
            p = $" {p} ";
            var mapped = summaries
                .Where(s => s.Value.Contains(p))
                .Select(s => Unbrace(s.Parent.Attribute("name").Value ?? ""))
                .ToHashSet();
            if (mapped.Count == 0)
                mapped = MyMap.Where(s => s.Key.Contains(p)).Select(s => s.Value).ToHashSet();
            return mapped.Select(s => $"<span class='dotnet'>{Shorten(s)}&nbsp;<a href='{MsdnLink(s)}' target='_blank'>♯</a></span>").ToArray();
        }

        static string MsdnLink(string s)
        {
            if (s[1] == ':')
                s = s[2..];
            return $"https://docs.microsoft.com/en-us/dotnet/api/{s.Replace('`', '-').ToLower()}?view=netcore-3.1";
        }

        static string Shorten(string s)
        {
            if (s[1] == ':')
                s = s[2..];
            if (s.StartsWith("System.Runtime.Intrinsics.X86."))
                return s["System.Runtime.Intrinsics.X86.".Length..];
            if (s.StartsWith("System.Runtime.Intrinsics."))
                return s["System.Runtime.Intrinsics.".Length..];
            return s;
        }
    }
}