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- Non-installed: orange.
- Installed but disabled: gray.
- Installed and enabled: green.
- Installed and enabled, but with warnings: red.
There is one additional "status": "Must have", in orange. Modules with this status are actually promoted from the Addons website. They are not free: the "Install" button is replaced by a shopping cart button, with the price of the module. Clicking that button open the module's page on the Addons website, where you can buy the module.
Most of the time, warnings are a reminder that you have not properly configured the module. Click its "Configure" link and go through the various needed steps.
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