This add-on causes two markup changes in of Google Calendar. Event names containing a colon (:) will have the part before the colon being displayed as a colored tag that helps discerning different kinds of events without the need for creating dozens of calendars. For example: "Tag: Event name" becomes "[Tag] Event name". Event names ending with a question mark will be displayed in italic and transparent, as a kind of optional or yet to be confirmed event. UPDATE 27/02/2024: This extension now also works in the embedded version of Google Calendar (to the right of Gmail for example). Google Calendar is a trademark of Google Inc. Use of this trademark is subject to Google Permissions.