Niche software products for auditors (4)

I believe the answer is:

apse

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'niche' is the definition.
(apse is a kind of niche)

I can't explain the rest of the clue.

(Other definitions for apse that I've seen before include "Where the altar is usually found in a church" , "Rounded end of building" , "Projection to the east end of a church" , "Church's part" , "Domed section of a church" .)

I've seen this clue in The Times.

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