Use of ratio as time separator and RTL languages is broken
The HIG suggests to use the unicode ratio symbol as time separator (https://developer.gnome.org/hig/guidelines/typography.html#take-advantage-of-unicode). However, this results in a difficult to figure out issue with RTL languages in which the time labels are reversed (GNOME/gnome-music#509 (closed), GNOME/gnome-music!946 (merged)).
Looking into to this I came across the following related links:
- https://ux.stackexchange.com/questions/122248/should-u2236-ratio-be-used-as-a-time-separator-instead-of-u003a-colon
- https://web.archive.org/web/20190108033419/https://blogs.msdn.microsoft.com/oldnewthing/20180913-00/?p=99725
- https://web.archive.org/web/20190108113711/https://medium.com/@amachino/the-secret-of-san-francisco-fonts-4b5295d9a745
So it looks like Windows had this idea as well, but they special-cased RTL languages. Apple uses the regular colon, but treats it differently depending on the context (and font?). The unicode standard itself uses the regular colon.
It might be best to rethink this suggestion. At least it should be mentioned that this needs some special attention, it is not a drop-in replacement.