The scholia to the Iliad as (a source of) indirect tradition

In relation to indirect tradition, scholiastic corpora have long been conceived as treasure troves of fragments of lost literature, given their habitual explanatory use of quotations. However, each corpus of scholia can also be considered a source of indirect tradition concerning the work upon which it comments, since it provides information about the state of the text in its ancient phases. Moreover a scholiastic corpus is an example of indirect tradition in itself, with regard to ancient paraliterary outputs that have constituted it in multiple steps of selection, abridgement, and compilation. This intertwined dynamic will here be scrutinized on the basis of some telling passages, with reference to the Iliad, whose scholia preserve a substantial legacy of ancient scholarship and bear traditional classes that provide crucial evidence of their ultimate (type of) sources.