.net core code to read a SharePoint SPPKG file

SPFxPackage.cs

using System;
using System.Collections.Generic;
using System.Linq;
using MSPackage = System.IO.Packaging;
using System.Text;
using System.Threading.Tasks;
using System.Xml.Linq;

namespace Jimmywim.SharePoint.Packaging
{
    public class SPFxComponent
    {
        public string Name { get; set; } = string.Empty;
        public string Type { get; set; } = string.Empty;
        public string Id { get; set; } = string.Empty;
    }

    public class SPFxPackage
    {
        public string Name { get; set; }
        public Version Version { get; set; }
        public string ProductId { get; set; }
        public List<SPFxComponent> Components { get; set; } = new List<SPFxComponent>();

        public static SPFxPackage LoadPackage(string path)
        {
            using var package = System.IO.Packaging.Package.Open(path);
            return ParsePackage(package);
        }

        public static SPFxPackage LoadPackage(byte[] packageBytes)
        {
            using var memorystream = new System.IO.MemoryStream(packageBytes);
            using var package = MSPackage.Package.Open(memorystream);
            return ParsePackage(package);
        }

        private static SPFxPackage ParsePackage(MSPackage.Package package)
        {
            XNamespace spNs = "http://schemas.microsoft.com/sharepoint/";
            SPFxPackage spfxPackage = new SPFxPackage();


            var rels = package.GetRelationshipsByType("http://schemas.microsoft.com/sharepoint/2012/app/relationships/package-manifest");
            if (rels.Any())
            {
                var manifestRel = rels.First();
                var packagePart = package.GetPart(manifestRel.TargetUri);

                using var partStream = packagePart.GetStream();
                XDocument xDoc = XDocument.Load(partStream);
                var appElem = xDoc.Root;

                var packageName = appElem.Attribute("Name").Value;
                var packageId = appElem.Attribute("ProductID").Value;
                var packageVersion = appElem.Attribute("Version").Value;


                var packageRelationships = packagePart.GetRelationships();
                foreach(var packageRel in packageRelationships)
                {
                    var relPart = package.GetPart(packageRel.TargetUri);
                    using var relPartStream = relPart.GetStream();
                    XDocument relxDoc  = XDocument.Load(relPartStream);

                    var features = relPart.GetRelationshipsByType("http://schemas.microsoft.com/sharepoint/2012/app/relationships/feature-elementmanifest");
                    foreach(var feature in features)
                    {
                        var featurePart = package.GetPart(feature.TargetUri);   
                        using var featureStream = featurePart.GetStream();
                        XDocument featureXDoc = XDocument.Load(featureStream);

                        var componentXml = featureXDoc.Root.Element(spNs + "ClientSideComponent");

                        if (componentXml != null)
                        {
                            var componetName = componentXml.Attribute("Name").Value;
                            var componentId = componentXml.Attribute("Id").Value;
                            var componentType = componentXml.Attribute("Type").Value;

                            spfxPackage.Components.Add(new SPFxComponent
                            {
                                Name = componetName,
                                Id = componentId,
                                Type = componentType,
                            });
                        }
                    }
                }

                spfxPackage.Name = packageName;
                spfxPackage.Version = new Version(packageVersion);
                spfxPackage.ProductId = packageId;

                return spfxPackage;
            }
            else
            {
                throw new ArgumentOutOfRangeException($"Package appears not to be an SPFx package");
            }
        }
    }
}