Interesting. Would this explain why doing a parallel build of our docs only makes thingsslower?

@mdboom I think so. I looked into this at some point we need to mark all the plugins we are using as parallel safe for that to work

What I was trying to say is that I think there are more extensions that need to be marked safe for this to work in our docs build

I'm playing around with parallel doc building in#5597. I don't think we need to wait for that to merge this, though. This will still help others who use the plot directive in their own projects.

@mdboom, exactly

backported to v2.x as591b6d6