How to use:

Enter a URL pattern to the URL input box
Click "Upload Image" button
Drag your favicon to the image uploading area, please make sure the response says it's uploaded successfully; You could also enter an link of an image.
Go to a URL that matches the pattern, the favicon of the page should be changed to what you just set.

Once uploaded an image: - click the image to update an new image - Use the switch to disable/enable this pattern (need to close the tab and reopen to see the updates) - click the remove button to remove this pattern. Sample URL Patterns:

calendar.google.com - To replace favicons for Google Calendar.
www.youtube.com - To replace favicons for YouTube.

- This extension will not upload your uploaded images to anywhere, all the images will be stored in the local indexedDB of your browser, so no need to worry about the security/privacy of your images. - This extension uses Javascripts' regular expression matching functionality to compare the urls with the patterns, so it supports much more complex url patterns. Limitations: * It can't modify the favicons for about:whatever pages, this is the limitation of web extensions. * It doesn't work well with bookmarks' favicons. I think it can change the bookmark's favicon if you have never bookmarked the page before, however I think Firefox caches favicons in some ways, so if you've bookmarked the page before, this extension won't be able to change it. Credits: - The icon of this extension is made by Gregor Cresnar from flaticon.com.

Réponse du développeur