The Telerik.Web.PDF assembly is not included in the Kendo UI bundle. It is available in the Telerik UI for ASP.NET MVC bundle, the trial including. You can get the bundle from the product's download page here: https://www.telerik.com/account/product-download?product=KENDOUIMVC
Once you download the telerik.ui.for.aspnetmvc.2020.3.1021.trial.zip archive, you can find the assembly in the \pdfviewer\binaries\netstandard\ folder.
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