I see it too, because I block web fonts. Enabling web fonts resolves the issue.
For me, this is some kind of Linux + Firefox + certain fonts issue with the ’ character (right single quotation mark, not '). We're not the first to run into it: https://bugzilla.mozilla.org/show_bug.cgi?id=48152 but reproducing seems quite hard.
- font-family is "Source Sans Pro","Microsoft Yahei",sans-serif
- Source Sans Pro has no fallback font
- the fallback font for Microsoft Yahei is Noto Sans CJK SC (result of ~ $ fc-match 'Microsoft Yahei') because YaHei is a CJK optimised font. This is configured in /etc/font/conf.d/30-cjk-aliases.conf
- Noto Sans CJK SC is a wide font (common for CJK fonts)
I think the solution to this problem is altering config files in /etc/fonts/conf.d somehow but I haven't figure out what I need to change exactly. Commenting out lines 466-473 (the alias containg <family>Microsoft YaHei</family>) to kill the association works, but I'm pretty sure that breaks any attempt to render MS YaHei.
For me, this is some kind of Linux + Firefox + certain fonts issue with the ’ character (right single quotation mark, not '). We're not the first to run into it: https://bugzilla.mozilla.org/show_bug.cgi?id=48152 but reproducing seems quite hard.
According to https://www.reddit.com/r/firefox/comments/is9twh/why_would_a..., this happens when you have Chinese (I'm guessing Asian) fonts installed.
The reason, as far as I can tell:
- font-family is "Source Sans Pro","Microsoft Yahei",sans-serif
- Source Sans Pro has no fallback font
- the fallback font for Microsoft Yahei is Noto Sans CJK SC (result of ~ $ fc-match 'Microsoft Yahei') because YaHei is a CJK optimised font. This is configured in /etc/font/conf.d/30-cjk-aliases.conf
- Noto Sans CJK SC is a wide font (common for CJK fonts)
I think the solution to this problem is altering config files in /etc/fonts/conf.d somehow but I haven't figure out what I need to change exactly. Commenting out lines 466-473 (the alias containg <family>Microsoft YaHei</family>) to kill the association works, but I'm pretty sure that breaks any attempt to render MS YaHei.