Each Project you create in Demeter (opens in a new tab) has access to all extensions available, but you are the one in control of which extensions you want to have enabled, depending on your usage needs. To view the complete list of extensions you can access your Project Development Console
Go to the home page and select the Projects button.
Then, select the Open button of the project you want to work with to access the Development Console.
Select the Browse Extensions button.
Once in the Extensions browser, you'll see the list of all extensions available.
In the extensions tab, select the extensions you want to enable. In the following example, I'll select the "Cardano Ogmios" extension.
Then, enable the extension according to the network of your preference to start using it.
In the Development Console, you'll see the active extensions list. Select the extension you want to disable.
You can disable it with the switch button. Once you disable an extension, you'll see an "Instance disconnected" message and then it will be removed from the list.
Once you disable an extension, you'll see an "Instance disconnected" message and then it will be removed from the list.
When you disable an extension, it will stop consuming resources for your Project, so it's very important for optimizing the DCUs available for your project only to enable the extensions you need when you need them.