[Metadatalibrarians] What's a good MARC field for indicating that something is an open educational resource

[Wilhelmina Randtke]

I work with MODS mostly and have a MARC question.

For an upcoming harvesting project, using MARC, there is a need to separate
open educational resources from digital library resources generally.

What's a good MARC field to indicate this in?  Maybe something with a genre
reference and there's an existing genre for open educational resources?
The field would be added as part of the harvesting script, so suggestions
for a perfect-MARC-world are totally doable.  The source metadata doesn't
have to have the indicator, and it would be added on a
collection-by-collection/harvest-by-harvest basis.

If anyone has looked at this, and has a clean place to store the info in
MARC, I'm very grateful for a shout out.

Best,

-Wilhelmina Randtke