Add `OFFICIAL_CASK_TAPS` in `official_taps.rb`.

Library/Homebrew/cmd/search.rb

@@ -100,10 +100,8 @@ module Homebrew
     raise SEARCH_ERROR_QUEUE.pop unless SEARCH_ERROR_QUEUE.empty?
   end
 
-  SEARCHABLE_TAPS = OFFICIAL_TAPS.map { |tap| ["Homebrew", tap] } + [
-    %w[caskroom cask],
-    %w[caskroom versions],
-  ]
+  SEARCHABLE_TAPS = OFFICIAL_TAPS.map { |tap| ["Homebrew", tap] } +
+                    OFFICIAL_CASK_TAPS.map { |tap| ["caskroom", tap] }
 
   def query_regexp(query)
     case query

Library/Homebrew/official_taps.rb

@@ -5,6 +5,11 @@ OFFICIAL_TAPS = %w[
   science
 ].freeze
 
+OFFICIAL_CASK_TAPS = %w[
+  cask
+  versions
+].freeze
+
 OFFICIAL_CMD_TAPS = {
   "homebrew/bundle" => ["bundle"],
   "homebrew/test-bot" => ["test-bot"],