The OSF is an incorporated body having charitable status under the Charities and Trustee Investment (Scotland) Act 2005. It is a Scottish Charitable Incorporated Organisation (SCIO) with a single tier structure and registered charity number SC045392. The OSF’s details as held by the Office of the Scottish Charity Regulator can be seen here https://www.oscr.org.uk/search-oscr/charity-details?number=SC045392#results.
If you wish to see the OSF’s constitution, you can download it from here.