This function is used to find any item, catalogue, export within RDMP. The shortcut for this function is Ctrl F.
Using this function within Cohort Builder, Catalogues, Data Export etc will look for items specifically there unless specified to search elsewhere, this can be done by selecting the different icons along the top of the 'Find' pop up box shown below 
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Find can also be used by typing the letter of the search name followed by what by what you are looking for: ie cic test ie cic test will bring up all items in cohort identification config called test. For example : cic test (this will bring all in the cohort identification config called with test in the title).
This is the list of filters with their corresponding letter:
Catalogue (c)
Catalogue Item (ci)
Supporting Document (sd)
Project (p)
Extraction Configuration (ec)
Extractable Cohort (co)
Cohort Identification Config (cic)
Table Info (t)
Column Info (col)
Load Metadata (lmd)