The description ‘capital-allotment-shares’ returns more data in ‘description_values’ that there are placeholders for in the description.
‘capital-allotment-shares’ : “Statement of capital following an allotment of shares on {date}”
For example, for document ID https://document-api.companieshouse.gov.uk/document/ynI8g0LvFLj6wylhu236Q1u6dE-llGFGB-MgFt1Wqsg
, its 'description’ short-code is ‘capital-allotment-shares’, and as you can see above there is one item for replacement, i.e. {date}.
However, in ‘description_values’, 2 items are present - ‘date’ and ‘capital’, with capital itself being a list containing a dictionary with 2 items, ‘currency’ and ‘figure’.