How to make custom setting type

Hello all.

I am making plugin.
In settings file “settings.yml” i can add settings.
There is field: “type”, it can be for example “list”, and then “list_type” can be “secret”.
In output you get setting like “sso_provider_secrets”. One field for domain, one field for secret.
I need setting which is very like it, but contains 3 fields. So it is list of 3 fields. For example “domain”, “secret”, “alternate domain”. Something like that.

So my question is, where can i define custom setting rule? Where is rule “list_type -> secret” described? Where is described how it is rendered?
I would be glad for any help.



I’m also trying to achieve something similar but seems like the approach they took is following formats such as the one at @Johani uses at Custom Header Links but clearly it would be nice if we can create custom types.

Appreciate if you find the solution.

See the core setting yaml file, it’s using the list type of setting with placeholder