For macOS
Arc policies on macOS are stored in
~/Library/company.thebrowser.Browser.plist
You can make edits to this file by editing the file itself (note that this will require using software that allows you to edit these files, such as Xcode). You may also make edits to the .plist file from the macOS Terminal using the following command:
defaults write company.thebrowser.Browser.plist -[policy name] [value]
For example, if you want to disable all Max features in Arc, you would run the following command:
defaults write company.thebrowser.Browser.plist arcMaxDisabledByOrgPolicy true
If the value has an array, like URLBlocklist value, it will be in the format shown below.
defaults write company.thebrowser.Browser.plist URLBLocklist -array "<https://facebook.com>" "<https://www.example.com>"
The bundle identifier for Release channel of Arc is company.thebrowser.Browser.
For Windows
Arc policies for Windows are stored in %LOCALAPPDATA%\Packages\TheBrowserCompany.Arc_ttt1ap7aakyb4\LocalCache\Local\company.thebrowser.arc.plist
You can make edits to this file by editing the file itself (note that this will require using software that allows you to edit these files).
For example, if you want to disable all Max features in Arc, you would set the arcMaxDisabledByOrgPolicy value to true:
<key>arcMaxDisabledByOrgPolicy</key>
<true/>