With the rewrites configuration in next.config.js,
any route that does not exist is rewritten to /foo.

URLExpected resultActual result
/This pageThis page
/fooFOOFOO
/barBARBAR
/not-existing-routeFOOFOO
/enThis pageThis page
/en/fooFOOFOO
/en/barBARBAR
/en/non-existing-routeFOOFOO

However, the behavior seems to be bugged for the frontpage,
when adding GET params combined with i18n path.

URLExpected resultActual result
/?param=somethingThis pageThis page
/foo?param=somethingFOOFOO
/bar?param=somethingBARBAR
/non-existing-route?param=somethingFOOFOO
/en?param=somethingThis pageFOO
/en/foo?param=somethingFOOFOO
/en/bar?param=somethingBARBAR
/en/non-existing-route?param=somethingFOOFOO