hyphens: auto on all boxes. Do browsers hyphenate?

Upper case source code

Chrome: not English
Safari: yes
Firefox: no
Lower case source code

Chrome: yes
Safari: yes
Firefox: yes
Lower case source code, except single cap

Chrome: not English
Safari: yes
Firefox: only German
Lower case source code + text-transform

Chrome: not English
Safari: yes
Firefox: yes
CSS
IS
AWESOME
css
is
awesome
css
is
Awesome
css
is
awesome
CSS
IS
FANTASTISCH
css
is
fantastisch
css
is
Fantastisch
css
is
fantastisch
CSS
IST
FANTASTISCH
css
ist
fantastisch
css
ist
Fantastisch
css
ist
fantastisch
CSS
EST
MERVEILLEUX
css
est
merveilleux
css
est
Merveilleux
css
est
merveilleux

Safari is Mac/iOS.

All Chromia do the same as Chrome, though my Samsung Internet and Edge/Windows don't seem to have a Dutch dictionary. Interestingly, Chrome/Windows on the same system does have a dictionary, so it's applied on a per-browser basis, and not on a per-system basis.

The French hyphenation mer-veilleux is the only correct one. "veilleux" cannot be hyphenated again.

Firefox doesn't hyphenate any word that contains an uppercase character. Chrome does so in Dutch, German, and French, but not in English. Safari hyphenates even in English.
BUT if you use lower-case source code and text-transform: uppercase Firefox hyphenates it.

Historical note: I did these same tests in September 2021, and back then Chrome did support hyphenation of the first, CAPS-only example.

March 2023 - ppk