Here are the answers to the questions:

1. What tool was used for pathway enrichment analysis?
The tool used for pathway enrichment analysis is DAVID (Database for Annotation, Visualization and Integrated Discovery).

2. Was a tool version number provided?
Not described.

3. What gene set library was queried (eg: GO, KEGG, Reactome or other)?
Not described, but it is mentioned that the authors performed "DAVID Functional Annotation Clustering".

4. Was a background gene list defined for pathway enrichment analysis?
Not described.

5. What statistical test was used for enrichment analysis?
Not described.

6. Was false discovery rate correction used to control the number of false positives in the pathway enrichment analysis?
Not described, but it is mentioned that the authors identified "a set of differentially expressed genes with the strongest differences in pathways related to innate immune responses to pathogens and type I interferon signaling", suggesting that some kind of statistical correction may have been used, but the details are not provided.