CustomFloat!(5, 2).mant_dig should be 5, not 6. If storeNormalized is not set, it should be 4.
Meanwhile I found out, that mant_dig is defined differently, than I thought - the leeding 1, that is not saved in IEEE floats, is counted too. Therefore I changed title and component of this bug report. The documentation should mention, that this 1 is counted.
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