title: Azure Functions Not Generating extensions.json
body: <p>I have an Azure Functions Project with multiple functions, triggered by ServiceBus and BlobStorage.</p>
  
  <p>They have been building and deploying to azure fine for a couple months now.<br>
  <em>Something</em> happened recently and they are no longer deploying from my build machine with an error in Azure when you click on the function <code>Error: The binding type(s) 'blobTrigger' are not registered.</code><br>
  It is still deploying fine from my dev machine though.  They are using WEBSITE_RUN_FROM_ZIP to deploy the code itself.</p>
  
  <p>I pulled the publish directory from both my dev machine and the build machine and it appears that the file <code>extensions.json</code> is getting generated locally but is not on the build machine, along with empty localization folders that don't exist on the build machine and about 10mb difference in size that I can't account for yet.<br>
  The Azure Functions are targeting .Net Standard 2.0.  Checking the .Net versions, .Net core is the same version across the build and dev machines.</p>
  
  <p>What causes this file to get generated?</p>