How to configure filters using the YAML config option? Specifically cssrewrite. about webassets

[gg2]

So, I assume, now that I'm looking at it again a 2nd time, cssrewrite simply accepts no config from the environment.
The "manual mode" is the expectation for use.

If so, then I'd like to lobby for enabling "replace" as a config for cssrewrite, especially via YAML (presumably an option can be set via YAML by default, if environment.config can be set). For the platform I'm working with, I'm not sure they provide a means to hook into webassets before/after it runs, aside from simply setting up the YAML config. And I always dislike setting up custom hacks to make things work outside the regular flow.

Anyway, thank you for the consideration.

Also, now that I've had the presence of mind to find the environment config docs, I suppose the YAML might look more like this?

config:
    cssrewrite_replace:
        - ''
          'assets/js-themes/default/'
        - 'etc'
          ...

If I can't specify to simply add a prefix where there is none, and must use the regex replace, that would be helpful to elaborate in the docs. Thank you, again.