How the nightlight that found favour was spoken of? (9)

I believe the answer is:

glowingly

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'how' is the definition.
Both the definition and answer are adverbs. Maybe you can see a link between them that I don't see?

I cannot understand how the remainder of the clue works.

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(Other definitions for glowingly that I've seen before include "How Lampyris noctiluca shines" , "with great enthusiasm!" .)

I've seen this clue in the Evening Standard.

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