The `Array` type takes one parameter that describes the possible types
of the inner elements. This parameter may exist of pipes to indicate
multiple possible types. However, the current type definition provides
multiple parameters; this is incorrect syntax, and TypeScript 5.7+ now
fails on this due to stricter syntax validation.
This commit fixes the issue by changing the type definition to the
proper syntax, which together with the accompanying comment about the
contents of the fingerprints array should document it sufficiently.
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