i have adhd so instead of opening the example models in inochi creator and actually learning anything, i made a filetype association so i could open .inx files from my file manager
put thing in the new place
x-inx.xml
-> ~/.local/share/mime/packages
then update-mime-database ~/.local/share/mime
verify newly installed mimetype:
xdg-query filetype path/to/file.inx
# result should be 'application/x-inx'
# NOT 'application/octet-stream'
put other thing in the other new place
inochi-creator.desktop
-> ~/.local/share/applications
then update-desktop-database ~/.local/share/applications
enjoy opening .inx files from your browser or file manager