In Visual Studio 2019 Preview 2, The Web Tools team made some changes to improve extensibility features for extension developers. To standardize interfaces, the CSS, HTML, JSON and CSHTML editors renamed their assemblies as per the following table:
| Old | New |
| Microsoft.CSS.Core | Microsoft.WebTools.Languages.Css |
| Microsoft.CSS.Editor | Microsoft.WebTools.Languages.Css.Editor |
| Microsoft.Html.Core | Microsoft.WebTools.Languages.Html |
| Microsoft.Html.Editor | Microsoft.WebTools.Languages.Html.Editor |
| Microsoft.VisualStudio.Html.Package | Microsoft.WebTools.Languages.Html.VS |
| Microsoft.JSON.Core | Microsoft.WebTools.Languages.Json |
| Microsoft.JSON.Editor | Microsoft.WebTools.Languages.Json.Editor |
| Microsoft.VisualStudio.JSON.Package | Microsoft.WebTools.Languages.Json.VS |
| Microsoft.VisualStudio.Web.Extensions | Microsoft.WebTools.Languages.Extensions |
| Microsoft.Web.Core | Microsoft.WebTools.Languages.Shared |
| Microsoft.Web.Editor | Microsoft.WebTools.Languages.Shared.Editor |
To avoid potential parse issues, the JSON parse tree changed behavior. When you call JsonParserService.GetTreeAsync, you now get a snapshot of the JSON parse tree. As an extension developer, you can now request and maintain snapshots of the JSON parse tree.