Some languages requires a space separator between the first-punctuation and the first letter. Both the punctuation and the space separator should be included in the ::first-letter pseudo element.

Browsers treat this differently at the moment. Safari includes spaces, while Chrome does not.
https://bugs.chromium.org/p/chromium/issues/detail?id=638267.

At the moment the spec does not specify that space should be included: https://www.w3.org/TR/css-pseudo-4/#first-letter-pseudo

Examples:

French
The opening quotation mark in French cannot go without a space:
« Voulez-vous un sandwich, Henri ? »

Source: https://en.wikipedia.org/wiki/Quotation_mark#French

Norwegian
Some quotation marks in Norwegian (replikkstrek) cannot go without a space:
– Pettersen, ropte hun, – kom inn og få kaffe.

Source: https://www.sprakradet.no/sprakhjelp/Skriveregler/tegn/Tankestrek/