title: Create an Extension that is Identical to the Built-in Chrome Bookmarks Manager with Additional Features
body: <h2>Background</h2>
  <p>I understand there is a very similar post <a href="https://stackoverflow.com/questions/39619884/editing-built-in-chrome-bookmarks-manager-folder-sub-folder-auto-expansion">here</a>. But I could not do a follow-up comment because I don't have enough reputation yet... since I just recently joined.</p>
  <h2>Goal</h2>
  <p>I would like to create an extension that adds two things onto the current built-in chrome bookmark manager that would appear right below the URL box in the pop-up when you do star(bookmark) and click more. (could not post an image again because of reputation limit) First is a box for note-taking, where the notes will be searchable and editable within the bookmark manager. Second is another box for setting up a reminder to remind user to view the bookmark (very simple - only allows date and time)</p>
  <h2>Question</h2>
  <p>I don't want to drastically change anything about the current pop-up nor the manager. So I'm trying to avoid creating an extension from scratch. Instead, I wonder if extracting the relevant code from Chromium <a href="https://cs.chromium.org/chromium/src/chrome/browser/resources/bookmarks/" rel="nofollow noreferrer">source code</a> is feasible/legal as I don't have much experience in open-sourced projects? And then build on top of that to create an extension that basically is the same as the built-in bookmark manager but with additional features. Thank you!</p>
  <h2>Current state</h2>
  <p>I'm still looking at the Chromium <a href="https://cs.chromium.org/chromium/src/chrome/browser/resources/bookmarks/" rel="nofollow noreferrer">source code</a>. And I will update this post if I have any progress.</p>