Strange error in console after installing Font Awesome 4

Question

I have installed FontAwesome 4.7 without any file changing. Works alright. But why Firefox shows these strange warnings? There are a lot of them. Can't understand what is wrong.

<link rel="stylesheet" type="text/css" href="plugins/fa/font-awesome.min.css">

This is just a chunk from the console:

downloadable font: glyf: Glyph bbox was incorrect; adjusting (glyph 33) (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:1) source: http://localhost/cms/plugins/fa/fonts/fontawesome-webfont.woff2?v=4.7.0
downloadable font: glyf: Glyph bbox was incorrect; adjusting (glyph 55) (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:1) source: http://localhost/cms/plugins/fa/fonts/fontawesome-webfont.woff2?v=4.7.0
downloadable font: glyf: Glyph bbox was incorrect; adjusting (glyph 62) (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:1) source: http://localhost/cms/plugins/fa/fonts/fontawesome-webfont.woff2?v=4.7.0
downloadable font: glyf: Glyph bbox was incorrect; adjusting (glyph 81) (font-family: "FontAwesome" style:normal weight:400 stretch:100 src index:1) source: http://localhost/cms/plugins/fa/fonts/fontawesome-webfont.woff2?v=4.7.0

Answer 1

I'd filed this issue as a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1851623

The warnings are because there are some errors with the font itself.

In my just updated Firefox Dev 118.0b5 the warnings are still present but are less noisy.

Answer 2

Firefox decided to start alerting font creators when their glyphs extend outside the bounding box. The was intentional. If you are getting A LOT of messages (one for each character), then update to the latest version of Firefox where it will only warn once per font file.

If you are specifically using Font-Awesome 6 they are already working on a fix:

• https://github.com/FortAwesome/Font-Awesome/issues/19925

If you are getting this from a different font, then alert the font creator, so they can fix it.

Font-Awesome has said they will not update previous versions of the font to remove the warning. You can either update to their latest version, live with the warnings, or switch to a different approach for icons.

In the mean time you can uncheck the Warnings button in the dev console to hide these messages until your fonts can be updated or replaced.