Lexitec blogi

This happened to me. I updated the favicon of my site, it was updated automatically in XUL Firefox but Quantum Firefox refused to change the icon. It showed the correct icon in the tab but the old one in Booksmarks toolbar. If you have a parallel XUL Firefox instance, bookmark sharing does not fix the icons. I have read on the Net that some people have tried to modify Firefox bookmarks databases. I think this is not advisable as the solution is simple, and readily at hand. I was at a loss with how to proceed for a long time but I finally discovered the easy solution. All you need is another browser that shows the right bookmark icon. Choose Export bookmarks in order to create a Netscape Bookmark File (bookmarks.html with <!DOCTYPE NETSCAPE-Bookmark-file-1> in the header), see specification at https://learn.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/aa753582(v=vs.85). Almost all browsers (e.g. Chrome, Edge, etc.) support this import/export option. It stores the icons, and they are correctly retrieved by Quantum Firefox. You can even use your XUL Firefox to export to bookmarks.html as it does not have this lingering favicon bug. This method gets the right (favicon) bookmark icon to show but it has no effect on the icon shown in the tab (as it always shows the current favicon). Import only the bookmark you really need otherwise you may have to do some serious manual bookmark editing afterwards in Manage Booksmarks to delete any additional (duplicate) bookmarks that may have been imported. The bookmarks file can be edited by removing unnecessary entries with a text editor (refer to the above-mentioned specification when doing the editing). You only need one relevant entry of type '<DT><A HREF="{url}" ADD_DATE="{date}" LAST_VISIT="{date}" LAST_MODIFIED="{date}">{title}</A>' embedded in the correct bookmarks file structure.

When filled with actual ICON data, the bookmarks entry looks like this :
<DT><A HREF="https://www.mysite.com/" ADD_DATE="1676364167" LAST_MODIFIED="1676364585" ICON_URI="https://www.mysite.com/favicon.png" ICON="data:image/png;base64,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">MySite.com</A>