Ij is non ambiguously not Dutch IJ nor Dutch ij and should not be selected as a single grapheme for ::first-letter.

[r12a]

Test link(s):

test

Results:

• Gecko: ❌ Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/112.0
• Blink: ✅ Works, but ij is not treated as a typographic unit. Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36
• Webkit: ✅ Ditto Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.4.1 Safari/605.1.15

Related tests: Styling initials