Yep. These docs are focused on both Arabic and Persian language use of the Arabic script. (We'd like to also work Arabic script used for languages like Uighur and Urdu, if we can find collaborators.)
Just updated: "Inline markup and bidirectional text in HTML" w3.org/blog/International/20… Update brings it in line with recent browser developments and simplifies the guidelines. Examples link to live versions, and browser support information has been added.
Out for review: Updated article, Inline markup and bidirectional text in HTML w3c.github.io/i18n-drafts/ar… . Guidelines simplified, browser support info added, live tests added to examples, etc. Feedback via the link by 12 Dec please.