  The libraries of proof assistants like Isabelle, Coq, HOL are notoriously
difficult to interpret by external tools: de facto, only the prover itself can
parse and process them adequately. In the case of Isabelle, an export of the
library into a FAIR (Findable, Accessible, Interoperable, and Reusable)
knowledge exchange format was already envisioned by the authors in 1999 but had
previously proved too difficult. After substantial improvements of the Isabelle
Prover IDE (PIDE) and the OMDoc/Mmt format since then, we are now able to
deliver such an export. Concretely we present an integration of PIDE and MMT
that allows exporting all Isabelle libraries in OMDoc format. Our export covers
the full Isabelle distribution and the Archive of Formal Proofs (AFP) -- more
than 12 thousand theories and locales resulting in over 65GB of OMDoc/XML. Such
a systematic export of Isabelle content to a well-defined interchange format
like OMDoc enables many applications such as dependency management, independent
proof checking, or library search.
