The SH uses this index list to validate the target of summary indexed data, provide typehead for users using index=*. It's my current understanding that this is also used to calculate | rest /services/data/indexes based on testing on-prem.
I am concerned that Splunk Cloud doesn't seem to be being creating these in my cloud environment on the search heads that I did not create the index from. The issue is that for things like multi-select dashboard inputs that use this API to select index and IDM input set up, Splunk doesn't know about Indexes that I created on my Search Head/IDM/ES server. Originally Support told me to delete the index and recreate it on the IDM to set up the Modular input to use that Input. Users are complaining about apps that we use wanting to use the rest API query for indexes.
Have others dealt with this and found solutions with Splunk Support?
If you have independent search heads (as opposed to a SHC) then indexes created via one SH will be unknown to the other(s). One solution to that is to create an app (called, for example, myorg_all_indexes) and put the indexes.conf file there (you'll also need app.conf). Install the app on the SHs and the IDM. Splunk Cloud will automatically install the app on the indexers. The process is a little longer than using the GUI, but it keeps everything in sync.
--- If this reply helps you, an upvote would be appreciated.