Unknow command (__f!=v) in search log at job inspector

[manuelostertag]

Hello,

I've create a search which contains (...(CallerCountry="CN")).

When I take a look in the search log in the job inspector (to getting information about my search), I wonder why Splunk change the original (...(CallerCountry="CN")) to (...(__f!=v OR CallerCountry="CN")). The result of this search is "better" then the result of my original search.

Did anybody knows what __f!=v means? I couldn't find anything about it in the Splunk documentation?

PS: I use Splunk Enterprise 8.0.8

Thanks for your support

Manuel