  Ten years ago, the Mathematics Subject Classification MSC 2010 was released,
and a corresponding machine-readable Linked Open Data collection was published
using the Simple Knowledge Organization System (SKOS). Now, the new MSC 2020 is
out.
  This paper recaps the last ten years of working on machine-readable MSC data
and presents the new machine-readable MSC 2020. We describe the processing
required to convert the version of record, as agreed by the editors of zbMATH
and Mathematical Reviews, into the Linked Open Data form we call MSC2020-SKOS.
The new form includes explicit marking of the changes from 2010 to 2020, some
translations of English code descriptions into Chinese, Italian, and Russian,
and extra material relating MSC to other mathematics classification efforts. We
also outline future potential uses for MSC2020-SKOS in semantic indexing and
sketch its embedding in a larger vision of scientific research data.
