This (but for dark mode) https://addons.mozilla.org/en-US/firefox/addon/new-tab-button-for-toolbar

Install

• License: Mozilla Public License 2.0
• Weekly downloads: 0
• Average daily users: 1
• Rating: 0/5 of 0 ratings
• Created: 2023-06-25 17:03:44
• Last updated: 2023-06-26 07:00:40
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/new-tab-button-dark-mode/
• API: {0788a2f6-42a3-49bf-9512-65ba9ae6b09c}