Select a rectangle and sum all durations (like 3:21) inside of it.
This can be useful in sites like Bandcamp

Install

• License: GNU Lesser General Public License v2.1 or later
• Weekly downloads: 0
• Average daily users: 2
• Rating: 0/5 of 0 ratings
• Created: 2021-03-12 23:28:24
• Last updated: 2021-03-14 22:15:19
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/sumer/
• API: {639d69d5-00c6-44d4-a906-403d22f7e125}