On GIMP we have the possibility of an array with 4 dimensions and 6 behavior parameters: Incremental, Random, Angular, Speed, Pressure, and Tilt (x and y).
See documentation in https://docs.gimp.org/2.10/en/gimp-usin ... ushes.html

On Krita we have 5 behavior parameters: Constant, Incremental, Pressure, Random, and Angle.
https://docs.krita.org/en/general_conce ... %20brushes
https://docs.krita.org/en/tutorials/kri ... ush%20tips

So, Krita seems to support only brushes with a single dimension.
Another thing the Constant parameter it hasn't part of GIMP .GIH specification... Krita has a dedicated specification for the .GIH brushes?

It seems so at first sight but I haven't done any experiments in GIMP or Krita to verify that. If GIMP has facilities that you can't find in Krita (or vice versa) then you can run both at the same time and copy/paste layers between GIMP and Krita in either direction.

constant has likely been removed from gimp's version somewhere in the past, the original implementation was done by Lukas and he hasn't had time to work on Krita for several years. This is the only documentation there is on Gimp's format, so it would need someone interested to read this and to convert it to work for Krita's implementation.

Just as a matter of interest, I made a simple 2-dimensional .gih brush in GIMP (two cells per layer) and brought it into krita. Krita can't seem to understand the intent of the mapping from which control input to which dimension (perhaps not surprising). If you open the .gih file, krita will isolate each cell in a separate layer so it does seem to 'understand' the cell structure at least, so it converts it to a 1-D brush with all the dimensions stretched out along one dimension. You then need to Export this as a krita .gih brush, if you want to.