I found out that i need the Extension Extension:BetaFeatures to enable this extension. But stil after i enable this extension with the new "Beta" menu it still don't show anything only the search bar is visible but no menues. So maybe there are additional requirements for installation?
Topic on Extension talk:AdvancedSearch/Flow
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Hi @TomyLee.
The BetaFeatures extension should not be required by the extension. If this is a case than we should file a BUG and get that fixed!
However as @Jkmartindale says below you do need to have CirrusSearch!
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A bit of a long shot, but do you have Extension:CirrusSearch installed with all of its dependencies?