By default, which field would be listed in the fields sidebar under interesting Fields?

In Splunk, interesting fields are those fields that can provide valuable insights for analysis and are determined by their relevance to the given context of the data being examined. The field that is typically listed under interesting fields by default is the index.

The index field is critical as it indicates where the data resides within the Splunk infrastructure, helping users quickly identify the source of the data for search queries or reports. Being able to see the index allows users to make informed decisions about their data and whether they need to dive deeper into that specific index or adjust their search parameters.

The other fields, like host, source, and sourcetype, are indeed important in their contexts but do not take precedence as the default interesting field in the sidebar. The index serves as a foundational element in Splunk's architecture, emphasizing its importance in the overall data searching and retrieval process.