I read a Psalm each day, and have really appreciated having the Psalms Explorer to hand to help as I read them. Normally the annotation is fairly self-explanatory, but this morning I came across the following in Psalm 52:

I get Hebrew parallelism, and realise that in Hebrew the bit marked "a" comes before the bit marked "b", but I wondered if there is anything anywhere explaining the way they have tagged the parallelism in the Psalms?