Compensatory prolongation

The mechanic

When stopping on a word that ends in tanween fath, the tanween is dropped and an alef sound is given in its place. The written alef is already there in the mushaf.

Where it occurs

Its condition

ا

Length, as reported

Two harakat is what is reported, as with the natural madd.

A place in the text

وَرَأَيۡتَ ٱلنَّاسَ يَدۡخُلُونَ فِي دِينِ ٱللَّهِ أَفۡوَاجٗا

The marked spot was located in this ayah's own text at build time — An-Nasr 110:2.