RandomSource is a source for AltStore. It provides the app with information and files for installing other tweaked apps that you can’t get anywhere else, since the App Store has very restrictive guidelines.
RandomSource has jailbreak apps, media apps, tweaked apps, apps that have been removed from the App Store, and more.
Note: currently, it’s not very active, due to the Sources feature not being available to the public. It’s not like it’s not ready, and it appears to be only due to the developer’s greed. It’s been ready for about a year now, and multiple promises to release it have been made, but the developer hasn’t come through.
Once Sources become public, this will become active again.