Thanks for spotting my error – and sorry for my subsequent confusion! It appears I had used the Unicode version of the standard, and it seems exactly this is described in the article as "The ICU implementation, recorded in Version 1.4.1 of the Common Locale Data Repository sponsored by Unicode, uses a prime instead of a horn in the transliteration of consonants". 𝟙𝟤𝟯𝟺𝐪𝑤𝒆𝓇𝟷𝟮𝟥𝟜𝓺𝔴𝕖𝖗𝟰 (𝗍𝗮𝘭𝙠) 13:24, 23 March 2021 (UTC)