This is a plugin for the Redactor Rich-Text-Editor by modmore (https://www.modmore.com/extras/redactor/) that removes the padding around the editor and makes the toolbar a little bit bigger for a better integration into the MODX Manager.
Install the package through the modmore (NOT MODX.com) package provider! (It's free!) More information about the modmore package provider can be found at: https://www.modmore.com/about/package-provider/