Unzipping the challenge file, provides us with inferno.txt containing:
RCdgXyReIjdtNVgzMlZ4ZnZ1PzFOTXBMbWwkakdGZ2dVZFNiYn08eyldeHFwdW5tM3Fwb2htZmUrTGJnZl9eXSNhYFleV1Z6PTxYV1ZPTnJMUUpJTkdrRWlJSEcpP2MmQkE6Pz49
PDVZenk3NjU0MzIrTy8uJyYlJEgoIWclJCN6QH59dnU7c3JxdnVuNFVxamlubWxlK2NLYWZfZF0jW2BfWHxcW1pZWFdWVVRTUlFQMk5NRktKQ0JmRkU+JjxgQDkhPTw1WTl5NzY1
NC0sUDAvby0sJUkpaWh+fSR7QSFhfXZ7dDpbWnZvNXNyVFNvbm1mLGppS2dgX2RjXCJgQlhXVnpaPDtXVlVUTXFRUDJOR0ZFaUlIR0Y/PmJCJEA5XT08OzQzODFVdnUtMiswLygn
SysqKSgnfmZ8Qi8=
Again with the Base64. Again, it can be decoded in CLI or at https://www.base64decode.org/
$ cat inferno.txt | base64 -d
D'`_$^"7m5X32Vxfvu?1NMpLml$jGFggUdSbb}&
Looking back to the Decode Me Crypto challenge, I recognize the string as Malbolge programming language and we will use the same complier we used for the Decode Me Challenge.
https://www.tutorialspoint.com/execute_malbolge_online.php
HTB{!1t_1s_just_M4lb0lg3_l4ngu4g3!}