About the file
The editor.css is the file responsible for providing styles that should be used within the TinyMce WYSIWYG editor that Integra uses in the Public site(eg. to change the default text color or background of the editor). The "editor.css" file will loaded after the default CSS ("content.css") of the editor, so you can use it to override. It will influence the elements in this iframe only.
If you plan to use it in non-Integra pages, have in mind that the ui package version is part of the file's path as it is used as cache breaker.
The editor.css file, like the other ui package files, is distributed and installed in a skin&layout bundle and you can access them on the following paths:
- UI package root (the ui package install folder, with the version used as cache breaker)
How to use it
Using this file outside Integra is achievable but not easy. You should refer to the TinyMce documentation for more details