I have the following data structure:

[Log] [ (panel, line 126)
Object
countries[]: Array[2]
    0: "de"
    1: "en"
rate: "3 %"
]

And would like to output it with:

{{rate}}: {{countries[]}}

Sadly, this isn't working. The square brackets in the key name countries[] seem to be the problem. They get created by the CMS. If I remove them manually, {{rate}}: {{countries}} works. Any idea how to make it work with the square brackets in the key?