@mscroggs has all the details regarding this.
I’ll leave a brief summary here:
- The input mesh ordering is not kept, see: Quad mesh nodes reordered upon reading XDMF file - #2 by dokken
- As mentioned in this post, DOLFINx uses dof-permutations to make integrals map back to the reference element, see: [2102.11901] Construction of arbitrary order finite element degree-of-freedom maps on polygonal and polyhedral cell meshes
for details.