title: Chrome Notification API (for Extensions!) How to Re-enable Once Blocked?
body: <p>I have spent considerable time researching this and hopefully I have just missed something so I thought I would bounce it off the StackExchange community as well.</p>
  
  <p>Background:</p>
  
  <p>On latest Chrome > 65, all of the notifications are stores on a per-site basis, so if one were to grant or deny notification popup for a SITE and want to reverse that decision (accidentally clicked the "block" for example) they can simply go into Chrome notification settings, find that specific site, and remove the block.  This works as designed today and is well documented.</p>
  
  <p>So here is the issue detail in a scenario:</p>
  
  <p>Now, that exact same mechanism is used for extensions.  An extension is initially granted all it's required permissions and works properly.  Then, the user accidentally clicks "block" one time on a single desktop notification from the extension using the "gears" cog-wheel icon on the notification which then changes the notify balloon to this prompt:</p>
  
  <p><a href="https://i.stack.imgur.com/2EYdf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2EYdf.png" alt="https://i.imgur.com/f7Rp0B1.png"></a></p>
  
  <p>Now, any time that extension attempts to send a notify message, instead of the normal desktop notify, an ugly javascript notify pops up in the middle of the screen (with the exact same notify text), and two buttons - "OK" and "Cancel".  All extension functionality is unchanged if "OK" is clicked for example, the very same functions fire as if the user had clicked the prior desktop notify balloon popup.</p>
  
  <p>Here are two screenshots of this exact scenario using the popular Tampermonkey Chrome extension (using a randomly selected script with a known update) that uses desktop notification API to communicate script updates:</p>
  
  <p>"Normal" desktop notify message with default grant permission:</p>
  
  <p><a href="https://i.stack.imgur.com/VftE9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VftE9.png" alt="https://i.imgur.com/JLn9y1c.png"></a></p>
  
  <p>The exact same message (appears in center of the screen) once that permission is revoked by user clicking "block". **Note the actual message itself is not blocked which I find odd, just the desktop notify GUI bubble:</p>
  
  <p><a href="https://i.stack.imgur.com/tTkn7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tTkn7.png" alt="https://i.imgur.com/yR31pos.png"></a></p>
  
  <p>So, the question is really 2-fold:</p>
  
  <ol>
  <li><p>Where does Chrome store that boolean value of PermissionLevel FOR EXTENSIONS - as they do NOT appear in the normal list of granted/blocked SITES.  If not in the UI, is this setting exposed in a configuration file or is there even currently any way in Chrome>65 for the user to ever reverse this decision?</p></li>
  <li><p>Is there either a programmatic method that can be implemented by an extension developer on the back-end to ever check if this has occurred and re-prompt the user to change their mind and re-grant that permission?  I have found a couple unofficial posts here saying common sense says no to avoid malicious harassing of users etc. but I cannot find anything official.</p></li>
  </ol>