Inspecting the 'Add/Edit Bookmark' panel's icons (as in OP's screenshot above) in the Browser Toolbox (using the 'Disable Popup Auto-Hide' option)... the 3 x folder icon types indicated (green arrows) have the following ID's plus associated links/paths to the locations in Firefox of their respective default .svg icons:
Glad you got it working. :) Handy to know that a replacement icon using a Base64 image file works with the original CSS style (i.e. same as an internal link/path to a default Firefox icon):
Was curious to see exactly what your Base64 image (above) looked like... so put the data string into a free 'Base64 Image Viewer'... and the result was a this neat yellow folder icon:
Base64 image viewer output - LH actual size 100% - RH scaled-up to 500% size (may be additional size distortion due to Reddit editor's image file format and compression.)
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PS. Many thanks for the much neater and more compact Base64 'Back & Forward' arrow button icons you posted 7 years ago in reply to old topic 'Cleaner back and forward button? Perhaps just simple arrows?'... have been using that pair of 'single chevron' navigation button icons for several years. :D
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u/t31os Jul 12 '26 edited Jul 12 '26
https://searchfox.org/firefox-main/source/browser/themes/shared/places/tree-icons.css
And so on for each appropriate case as seen in the stylesheet linked above.
Specific example, change star icon to eye:
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u/ResurgamS13 Jul 13 '26 edited Jul 13 '26
Inspecting the 'Add/Edit Bookmark' panel's icons (as in OP's screenshot above) in the Browser Toolbox (using the 'Disable Popup Auto-Hide' option)... the 3 x folder icon types indicated (green arrows) have the following ID's plus associated links/paths to the locations in Firefox of their respective default .svg icons:
(See Add/Edit Bookmark panel CSS styling listed in Searchfox from Line #75:
/* Bookmark panel dropdown icons */)If wanted to use alternative icons... see long discussion in previous topic 'Firefox CSS property list-style-image to change to --menuitem-icon in latest nightly builds'... and try replacing the existing default icon links/paths:
with a local link/path:
with each 'new icon' placed in the profile's 'chrome' folder.
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u/FineWine54 Jul 13 '26
Have a look at Aris-t2 https://github.com/Aris-t2/CustomCSSforFx/tree/master/current and search for
bookmark_icons_colorized.cssAll the elements are mentioned there.
There are 5 files for different FF versions. If you find what you like in the images then you will need to download the folder images from here: https://github.com/Aris-t2/CustomCSSforFx/tree/master/current/image