Reads the text of every inline style block looking for the @import at-rule. An imported stylesheet cannot be discovered until the file importing it has downloaded and parsed, so each level of the chain adds a full sequential round trip to the render-blocking critical path.
Impact is importance multiplied by the confidence tier’s weight — SPECIFICATION 1.0, RESEARCH 0.7, EMERGING 0.3, EXPERIMENTAL 0.1. Two rules backed by the same class of evidence therefore always carry the same weight, which is what makes the score reproducible rather than hand-tuned.