icons.yaml not letting configure any new extensions except for default

[Necrom4]

• os: MacOs
• lsd --version: 1.1.2
• echo $TERM: xterm-256color
• echo $LS_COLORS: di=1;36:ln=35:so=32:pi=33:ex=31:bd=34;46:cd=34;43:su=30;41:sg=30;46:tw=30;42:ow=30;43

I copied the default .config/lsd/icons.yaml file and started modifying the icons, which works as expected.
If I add rb:  or anything else under extensions: (same for name: and filetype:), none of the changed icons show up anymore, and it all goes back to default.
Are we supposed not to add any other extensions to this config file?