• A limited report or chain is a report transmitted by a smaller number of narrators and not at the level of Tawatur described on this level.
• Qira'at here means the wording as read or recited. If additional wording or an explanatory phrase is reported about a Quranic passage only through a limited chain, that additional wording is not called Quran.
• The author attributes examples of such reports to Ubayy ibn Ka'b and Abdullah ibn Mas'ud رضي الله عنهما. They may be discussed as reports or explanations, but their extra wording is not added to the Quranic text on that basis.
What should you notice? The Quranic wording is one thing; reported explanation or additional recited wording that lacks Quranic Tawatur is another.