editor.css ??

[hameau]

I have never seen one of those. Is it new, or old and redundant info, or just something I never knew about?

It's a true story.

Provided that your css is not too radical, it can work very well with just a symbolic link named editor.css in the theme directory, pointing to the main style css file. It also renders the css typekit fonts in the editor window (but I have only tested where the fonts are served from the webserver, not from a CDN).

Adds a nice touch to the editor view.